Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- Sun Mar 14 09:26:59 2021
- Sun Mar 14 09:26:59 2021
- Sun Mar 14 09:26:59 2021 Msieve v. 1.53 (SVN 988)
- Sun Mar 14 09:26:59 2021 random seeds: 0543d3b0 29ab5d71
- Sun Mar 14 09:26:59 2021 factoring 273172217922179940865111564816996881998044676995415718434728922808941485760142122459544141922903710536431792693232615297389422827387902888326844652660911815295458564217037739798261039642551967739039758780271579 (210 digits)
- Sun Mar 14 09:27:00 2021 searching for 15-digit factors
- Sun Mar 14 09:27:00 2021 commencing number field sieve (210-digit input)
- Sun Mar 14 09:27:00 2021 R0: 5261613604543453659358513141525774210838453402
- Sun Mar 14 09:27:00 2021 R1: -72536980944504808218299
- Sun Mar 14 09:27:00 2021 A0: 1
- Sun Mar 14 09:27:00 2021 A1: 3
- Sun Mar 14 09:27:00 2021 A2: -3
- Sun Mar 14 09:27:00 2021 A3: -4
- Sun Mar 14 09:27:00 2021 A4: 1
- Sun Mar 14 09:27:00 2021 A5: 1
- Sun Mar 14 09:27:00 2021 skew 1.00, size 1.463e-015, alpha 2.379, combined = 1.206e-012 rroots = 5
- Sun Mar 14 09:27:00 2021
- Sun Mar 14 09:27:00 2021 commencing relation filtering
- Sun Mar 14 09:27:00 2021 setting target matrix density to 120.0
- Sun Mar 14 09:27:00 2021 estimated available RAM is 16151.1 MB
- Sun Mar 14 09:27:00 2021 commencing duplicate removal, pass 1
- Sun Mar 14 09:27:04 2021 error -15 reading relation 505651
- Sun Mar 14 09:27:27 2021 error -9 reading relation 3820033
- Sun Mar 14 09:29:23 2021 error -9 reading relation 21370729
- Sun Mar 14 09:30:32 2021 error -9 reading relation 31661107
- Sun Mar 14 09:31:18 2021 error -9 reading relation 38649982
- Sun Mar 14 09:31:58 2021 error -15 reading relation 44792954
- Sun Mar 14 09:32:36 2021 error -9 reading relation 50447947
- Sun Mar 14 09:33:08 2021 error -9 reading relation 55141793
- Sun Mar 14 09:33:17 2021 error -9 reading relation 56463857
- Sun Mar 14 09:33:18 2021 error -15 reading relation 56646315
- Sun Mar 14 09:34:24 2021 error -9 reading relation 66408722
- Sun Mar 14 09:34:40 2021 error -5 reading relation 68841750
- Sun Mar 14 09:34:44 2021 error -1 reading relation 69374776
- Sun Mar 14 09:34:56 2021 error -9 reading relation 71189097
- Sun Mar 14 09:34:57 2021 error -9 reading relation 71342987
- Sun Mar 14 09:34:58 2021 error -9 reading relation 71564167
- Sun Mar 14 09:35:04 2021 error -9 reading relation 72262663
- Sun Mar 14 09:35:04 2021 error -1 reading relation 72262771
- Sun Mar 14 09:35:34 2021 error -15 reading relation 76636877
- Sun Mar 14 09:35:35 2021 error -9 reading relation 76758231
- Sun Mar 14 09:35:42 2021 error -9 reading relation 77875809
- Sun Mar 14 09:35:51 2021 error -9 reading relation 79005416
- Sun Mar 14 09:35:56 2021 error -15 reading relation 79857351
- Sun Mar 14 09:35:57 2021 error -9 reading relation 79920681
- Sun Mar 14 09:35:58 2021 error -1 reading relation 80103598
- Sun Mar 14 09:36:00 2021 error -9 reading relation 80452623
- Sun Mar 14 09:36:01 2021 error -9 reading relation 80582517
- Sun Mar 14 09:36:03 2021 error -5 reading relation 80893370
- Sun Mar 14 09:36:04 2021 error -9 reading relation 80910157
- Sun Mar 14 09:36:04 2021 error -1 reading relation 81048877
- Sun Mar 14 09:36:07 2021 error -9 reading relation 81471277
- Sun Mar 14 09:36:12 2021 error -9 reading relation 82180025
- Sun Mar 14 09:36:15 2021 error -9 reading relation 82666948
- Sun Mar 14 09:36:16 2021 error -9 reading relation 82694244
- Sun Mar 14 09:36:17 2021 error -1 reading relation 82833889
- Sun Mar 14 09:36:18 2021 error -15 reading relation 82985256
- Sun Mar 14 09:36:19 2021 error -5 reading relation 83068115
- Sun Mar 14 09:36:25 2021 error -5 reading relation 84087895
- Sun Mar 14 09:36:39 2021 error -9 reading relation 86229958
- Sun Mar 14 09:36:42 2021 error -9 reading relation 86558394
- Sun Mar 14 09:36:48 2021 error -15 reading relation 87486413
- Sun Mar 14 09:36:54 2021 error -9 reading relation 88343000
- Sun Mar 14 09:36:59 2021 error -9 reading relation 89153458
- Sun Mar 14 09:37:05 2021 error -5 reading relation 90018152
- Sun Mar 14 09:37:35 2021 error -9 reading relation 94519320
- Sun Mar 14 09:37:46 2021 error -9 reading relation 96134646
- Sun Mar 14 09:37:46 2021 error -1 reading relation 96142520
- Sun Mar 14 09:37:49 2021 error -1 reading relation 96470637
- Sun Mar 14 09:37:49 2021 error -9 reading relation 96491447
- Sun Mar 14 09:38:07 2021 error -9 reading relation 99184520
- Sun Mar 14 09:38:10 2021 error -15 reading relation 99650095
- Sun Mar 14 09:38:16 2021 error -15 reading relation 100453780
- Sun Mar 14 09:38:27 2021 error -1 reading relation 102149663
- Sun Mar 14 09:38:36 2021 error -9 reading relation 103453668
- Sun Mar 14 09:38:47 2021 error -15 reading relation 105163821
- Sun Mar 14 09:38:48 2021 error -9 reading relation 105326103
- Sun Mar 14 09:38:49 2021 error -9 reading relation 105402794
- Sun Mar 14 09:38:49 2021 error -9 reading relation 105453704
- Sun Mar 14 09:38:58 2021 error -5 reading relation 106852243
- Sun Mar 14 09:38:59 2021 error -1 reading relation 106876938
- Sun Mar 14 09:39:15 2021 error -15 reading relation 109209828
- Sun Mar 14 09:39:26 2021 error -1 reading relation 110711834
- Sun Mar 14 09:39:27 2021 error -15 reading relation 110811065
- Sun Mar 14 09:39:41 2021 error -9 reading relation 113007904
- Sun Mar 14 09:39:43 2021 error -9 reading relation 113292786
- Sun Mar 14 09:39:43 2021 error -1 reading relation 113293817
- Sun Mar 14 09:39:44 2021 error -5 reading relation 113427176
- Sun Mar 14 09:39:44 2021 error -9 reading relation 113491316
- Sun Mar 14 09:39:50 2021 error -15 reading relation 114364955
- Sun Mar 14 09:39:53 2021 error -15 reading relation 114679136
- Sun Mar 14 09:40:07 2021 error -1 reading relation 116929716
- Sun Mar 14 09:40:08 2021 error -15 reading relation 116963199
- Sun Mar 14 09:40:08 2021 error -15 reading relation 116974849
- Sun Mar 14 09:40:37 2021 error -9 reading relation 121301540
- Sun Mar 14 09:40:37 2021 error -9 reading relation 121308576
- Sun Mar 14 09:40:37 2021 error -15 reading relation 121328615
- Sun Mar 14 09:40:41 2021 error -5 reading relation 121905987
- Sun Mar 14 09:40:48 2021 error -1 reading relation 123023615
- Sun Mar 14 09:40:50 2021 error -9 reading relation 123338335
- Sun Mar 14 09:40:51 2021 error -15 reading relation 123470011
- Sun Mar 14 09:40:54 2021 error -11 reading relation 123923115
- Sun Mar 14 09:40:55 2021 error -9 reading relation 123993024
- Sun Mar 14 09:41:08 2021 error -9 reading relation 126039954
- Sun Mar 14 09:41:09 2021 error -9 reading relation 126072966
- Sun Mar 14 09:41:11 2021 error -1 reading relation 126438319
- Sun Mar 14 09:41:11 2021 error -15 reading relation 126483274
- Sun Mar 14 09:41:12 2021 error -9 reading relation 126509180
- Sun Mar 14 09:42:13 2021 error -15 reading relation 135536873
- Sun Mar 14 09:42:34 2021 error -9 reading relation 138636331
- Sun Mar 14 09:42:34 2021 error -1 reading relation 138636332
- Sun Mar 14 09:42:35 2021 skipped 50 relations with b > 2^32
- Sun Mar 14 09:42:35 2021 skipped 68 relations with composite factors
- Sun Mar 14 09:42:35 2021 found 25332894 hash collisions in 138913110 relations
- Sun Mar 14 09:42:41 2021 added 2926300 free relations
- Sun Mar 14 09:42:41 2021 commencing duplicate removal, pass 2
- Sun Mar 14 09:44:01 2021 found 23259764 duplicates and 118579646 unique relations
- Sun Mar 14 09:44:01 2021 memory use: 660.8 MB
- Sun Mar 14 09:44:02 2021 reading ideals above 80019456
- Sun Mar 14 09:44:02 2021 commencing singleton removal, initial pass
- Sun Mar 14 09:55:11 2021 memory use: 2756.0 MB
- Sun Mar 14 09:55:12 2021 reading all ideals from disk
- Sun Mar 14 09:55:15 2021 memory use: 2068.2 MB
- Sun Mar 14 09:55:22 2021 commencing in-memory singleton removal
- Sun Mar 14 09:55:28 2021 begin with 118579646 relations and 86538297 unique ideals
- Sun Mar 14 09:56:39 2021 reduce to 90696398 relations and 56598808 ideals in 13 passes
- Sun Mar 14 09:56:39 2021 max relations containing the same ideal: 28
- Sun Mar 14 09:56:46 2021 reading ideals above 720000
- Sun Mar 14 09:56:46 2021 commencing singleton removal, initial pass
- Sun Mar 14 10:07:54 2021 memory use: 1506.0 MB
- Sun Mar 14 10:07:54 2021 reading all ideals from disk
- Sun Mar 14 10:08:00 2021 memory use: 3405.6 MB
- Sun Mar 14 10:08:15 2021 keeping 65477859 ideals with weight <= 200, target excess is 461439
- Sun Mar 14 10:08:27 2021 commencing in-memory singleton removal
- Sun Mar 14 10:08:39 2021 begin with 90696399 relations and 65477859 unique ideals
- Sun Mar 14 10:08:59 2021 reduce to 90696364 relations and 65477824 ideals in 2 passes
- Sun Mar 14 10:08:59 2021 max relations containing the same ideal: 200
- Sun Mar 14 10:09:50 2021 removing 7512015 relations and 5512015 ideals in 2000000 cliques
- Sun Mar 14 10:09:53 2021 commencing in-memory singleton removal
- Sun Mar 14 10:10:03 2021 begin with 83184349 relations and 65477824 unique ideals
- Sun Mar 14 10:11:11 2021 reduce to 82647502 relations and 59413569 ideals in 7 passes
- Sun Mar 14 10:11:11 2021 max relations containing the same ideal: 196
- Sun Mar 14 10:11:58 2021 removing 6079935 relations and 4079935 ideals in 2000000 cliques
- Sun Mar 14 10:12:00 2021 commencing in-memory singleton removal
- Sun Mar 14 10:12:09 2021 begin with 76567567 relations and 59413569 unique ideals
- Sun Mar 14 10:13:00 2021 reduce to 76202521 relations and 54959232 ideals in 6 passes
- Sun Mar 14 10:13:00 2021 max relations containing the same ideal: 188
- Sun Mar 14 10:13:43 2021 removing 5701657 relations and 3701657 ideals in 2000000 cliques
- Sun Mar 14 10:13:45 2021 commencing in-memory singleton removal
- Sun Mar 14 10:13:55 2021 begin with 70500864 relations and 54959232 unique ideals
- Sun Mar 14 10:14:51 2021 reduce to 70179654 relations and 50928109 ideals in 7 passes
- Sun Mar 14 10:14:51 2021 max relations containing the same ideal: 181
- Sun Mar 14 10:15:30 2021 removing 5502117 relations and 3502117 ideals in 2000000 cliques
- Sun Mar 14 10:15:32 2021 commencing in-memory singleton removal
- Sun Mar 14 10:15:41 2021 begin with 64677537 relations and 50928109 unique ideals
- Sun Mar 14 10:16:23 2021 reduce to 64371793 relations and 47112121 ideals in 6 passes
- Sun Mar 14 10:16:23 2021 max relations containing the same ideal: 171
- Sun Mar 14 10:17:00 2021 removing 5382663 relations and 3382663 ideals in 2000000 cliques
- Sun Mar 14 10:17:02 2021 commencing in-memory singleton removal
- Sun Mar 14 10:17:10 2021 begin with 58989130 relations and 47112121 unique ideals
- Sun Mar 14 10:17:49 2021 reduce to 58683133 relations and 43414798 ideals in 6 passes
- Sun Mar 14 10:17:49 2021 max relations containing the same ideal: 162
- Sun Mar 14 10:18:25 2021 removing 5301812 relations and 3301812 ideals in 2000000 cliques
- Sun Mar 14 10:18:27 2021 commencing in-memory singleton removal
- Sun Mar 14 10:18:34 2021 begin with 53381321 relations and 43414798 unique ideals
- Sun Mar 14 10:19:12 2021 reduce to 53065359 relations and 39787555 ideals in 6 passes
- Sun Mar 14 10:19:12 2021 max relations containing the same ideal: 154
- Sun Mar 14 10:19:45 2021 removing 5254488 relations and 3254488 ideals in 2000000 cliques
- Sun Mar 14 10:19:46 2021 commencing in-memory singleton removal
- Sun Mar 14 10:19:52 2021 begin with 47810871 relations and 39787555 unique ideals
- Sun Mar 14 10:20:31 2021 reduce to 47476939 relations and 36188132 ideals in 7 passes
- Sun Mar 14 10:20:31 2021 max relations containing the same ideal: 141
- Sun Mar 14 10:21:01 2021 removing 5232134 relations and 3232134 ideals in 2000000 cliques
- Sun Mar 14 10:21:02 2021 commencing in-memory singleton removal
- Sun Mar 14 10:21:08 2021 begin with 42244805 relations and 36188132 unique ideals
- Sun Mar 14 10:21:37 2021 reduce to 41881656 relations and 32579457 ideals in 6 passes
- Sun Mar 14 10:21:37 2021 max relations containing the same ideal: 129
- Sun Mar 14 10:22:04 2021 removing 5226329 relations and 3226329 ideals in 2000000 cliques
- Sun Mar 14 10:22:06 2021 commencing in-memory singleton removal
- Sun Mar 14 10:22:10 2021 begin with 36655327 relations and 32579457 unique ideals
- Sun Mar 14 10:22:40 2021 reduce to 36251514 relations and 28932829 ideals in 7 passes
- Sun Mar 14 10:22:40 2021 max relations containing the same ideal: 116
- Sun Mar 14 10:23:03 2021 removing 5242785 relations and 3242785 ideals in 2000000 cliques
- Sun Mar 14 10:23:04 2021 commencing in-memory singleton removal
- Sun Mar 14 10:23:08 2021 begin with 31008729 relations and 28932829 unique ideals
- Sun Mar 14 10:23:32 2021 reduce to 30544929 relations and 25204623 ideals in 7 passes
- Sun Mar 14 10:23:32 2021 max relations containing the same ideal: 104
- Sun Mar 14 10:23:53 2021 removing 5268978 relations and 3268978 ideals in 2000000 cliques
- Sun Mar 14 10:23:54 2021 commencing in-memory singleton removal
- Sun Mar 14 10:23:57 2021 begin with 25275951 relations and 25204623 unique ideals
- Sun Mar 14 10:24:17 2021 reduce to 24725750 relations and 21355024 ideals in 7 passes
- Sun Mar 14 10:24:17 2021 max relations containing the same ideal: 90
- Sun Mar 14 10:24:33 2021 removing 5309070 relations and 3309070 ideals in 2000000 cliques
- Sun Mar 14 10:24:35 2021 commencing in-memory singleton removal
- Sun Mar 14 10:24:37 2021 begin with 19416680 relations and 21355024 unique ideals
- Sun Mar 14 10:24:54 2021 reduce to 18731531 relations and 17313615 ideals in 8 passes
- Sun Mar 14 10:24:54 2021 max relations containing the same ideal: 76
- Sun Mar 14 10:25:07 2021 removing 2714814 relations and 1832168 ideals in 882646 cliques
- Sun Mar 14 10:25:08 2021 commencing in-memory singleton removal
- Sun Mar 14 10:25:09 2021 begin with 16016717 relations and 17313615 unique ideals
- Sun Mar 14 10:25:23 2021 reduce to 15689182 relations and 15139021 ideals in 8 passes
- Sun Mar 14 10:25:23 2021 max relations containing the same ideal: 68
- Sun Mar 14 10:25:33 2021 removing 89651 relations and 74760 ideals in 14891 cliques
- Sun Mar 14 10:25:34 2021 commencing in-memory singleton removal
- Sun Mar 14 10:25:36 2021 begin with 15599531 relations and 15139021 unique ideals
- Sun Mar 14 10:25:42 2021 reduce to 15599096 relations and 15063826 ideals in 4 passes
- Sun Mar 14 10:25:42 2021 max relations containing the same ideal: 68
- Sun Mar 14 10:25:45 2021 relations with 0 large ideals: 34955
- Sun Mar 14 10:25:45 2021 relations with 1 large ideals: 7920
- Sun Mar 14 10:25:45 2021 relations with 2 large ideals: 95765
- Sun Mar 14 10:25:45 2021 relations with 3 large ideals: 576895
- Sun Mar 14 10:25:45 2021 relations with 4 large ideals: 1859559
- Sun Mar 14 10:25:45 2021 relations with 5 large ideals: 3528490
- Sun Mar 14 10:25:45 2021 relations with 6 large ideals: 4641242
- Sun Mar 14 10:25:45 2021 relations with 7+ large ideals: 4854270
- Sun Mar 14 10:25:45 2021 commencing 2-way merge
- Sun Mar 14 10:25:58 2021 reduce to 10700466 relation sets and 10165196 unique ideals
- Sun Mar 14 10:25:58 2021 commencing full merge
- Sun Mar 14 10:31:35 2021 memory use: 1361.5 MB
- Sun Mar 14 10:31:38 2021 found 4769281 cycles, need 4763396
- Sun Mar 14 10:31:38 2021 weight of 4763396 cycles is about 571864023 (120.05/cycle)
- Sun Mar 14 10:31:38 2021 distribution of cycle lengths:
- Sun Mar 14 10:31:38 2021 1 relations: 151244
- Sun Mar 14 10:31:38 2021 2 relations: 229959
- Sun Mar 14 10:31:38 2021 3 relations: 292101
- Sun Mar 14 10:31:38 2021 4 relations: 320090
- Sun Mar 14 10:31:38 2021 5 relations: 338823
- Sun Mar 14 10:31:38 2021 6 relations: 346640
- Sun Mar 14 10:31:38 2021 7 relations: 344793
- Sun Mar 14 10:31:38 2021 8 relations: 333144
- Sun Mar 14 10:31:38 2021 9 relations: 315166
- Sun Mar 14 10:31:38 2021 10+ relations: 2091436
- Sun Mar 14 10:31:38 2021 heaviest cycle: 28 relations
- Sun Mar 14 10:31:41 2021 commencing cycle optimization
- Sun Mar 14 10:31:52 2021 start with 45435708 relations
- Sun Mar 14 10:34:27 2021 pruned 2490502 relations
- Sun Mar 14 10:34:27 2021 memory use: 1115.6 MB
- Sun Mar 14 10:34:27 2021 distribution of cycle lengths:
- Sun Mar 14 10:34:27 2021 1 relations: 151244
- Sun Mar 14 10:34:27 2021 2 relations: 235657
- Sun Mar 14 10:34:27 2021 3 relations: 304706
- Sun Mar 14 10:34:27 2021 4 relations: 335599
- Sun Mar 14 10:34:27 2021 5 relations: 358757
- Sun Mar 14 10:34:27 2021 6 relations: 367730
- Sun Mar 14 10:34:27 2021 7 relations: 368275
- Sun Mar 14 10:34:27 2021 8 relations: 354230
- Sun Mar 14 10:34:27 2021 9 relations: 334833
- Sun Mar 14 10:34:27 2021 10+ relations: 1952365
- Sun Mar 14 10:34:27 2021 heaviest cycle: 28 relations
- Sun Mar 14 10:34:35 2021 RelProcTime: 4055
- Sun Mar 14 10:34:35 2021
- Sun Mar 14 10:34:35 2021 commencing linear algebra
- Sun Mar 14 10:34:35 2021 read 4763396 cycles
- Sun Mar 14 10:34:47 2021 cycles contain 15345083 unique relations
- Sun Mar 14 10:36:10 2021 read 15345083 relations
- Sun Mar 14 10:36:47 2021 using 20 quadratic characters above 4294917295
- Sun Mar 14 10:37:44 2021 building initial matrix
- Sun Mar 14 10:41:07 2021 memory use: 1890.0 MB
- Sun Mar 14 10:41:12 2021 read 4763396 cycles
- Sun Mar 14 10:41:13 2021 matrix is 4763219 x 4763396 (2219.9 MB) with weight 633505908 (132.99/col)
- Sun Mar 14 10:41:13 2021 sparse part has weight 529547725 (111.17/col)
- Sun Mar 14 10:42:19 2021 filtering completed in 2 passes
- Sun Mar 14 10:42:20 2021 matrix is 4763175 x 4763352 (2219.9 MB) with weight 633504642 (133.00/col)
- Sun Mar 14 10:42:20 2021 sparse part has weight 529547447 (111.17/col)
- Sun Mar 14 10:42:36 2021 matrix starts at (0, 0)
- Sun Mar 14 10:42:37 2021 matrix is 4763175 x 4763352 (2219.9 MB) with weight 633504642 (133.00/col)
- Sun Mar 14 10:42:37 2021 sparse part has weight 529547447 (111.17/col)
- Sun Mar 14 10:42:37 2021 saving the first 48 matrix rows for later
- Sun Mar 14 10:42:39 2021 matrix includes 64 packed rows
- Sun Mar 14 10:42:40 2021 matrix is 4763127 x 4763352 (2126.1 MB) with weight 545917729 (114.61/col)
- Sun Mar 14 10:42:40 2021 sparse part has weight 509704342 (107.01/col)
- Sun Mar 14 10:42:40 2021 using block size 8192 and superblock size 1179648 for processor cache size 12288 kB
- Sun Mar 14 10:42:59 2021 commencing Lanczos iteration (4 threads)
- Sun Mar 14 10:42:59 2021 memory use: 1793.7 MB
- Sun Mar 14 10:43:37 2021 linear algebra at 0.0%, ETA 31h22m
- Sun Mar 14 10:43:46 2021 checkpointing every 170000 dimensions
- Mon Mar 15 16:24:30 2021 lanczos halted after 75325 iterations (dim = 4763126)
- Mon Mar 15 16:24:35 2021 recovered 35 nontrivial dependencies
- Mon Mar 15 16:24:36 2021 BLanczosTime: 107401
- Mon Mar 15 16:24:36 2021
- Mon Mar 15 16:24:36 2021 commencing square root phase
- Mon Mar 15 16:24:36 2021 handling dependencies 1 to 64
- Mon Mar 15 16:24:36 2021 reading relations for dependency 1
- Mon Mar 15 16:24:37 2021 read 2381513 cycles
- Mon Mar 15 16:24:43 2021 cycles contain 7670588 unique relations
- Mon Mar 15 16:25:37 2021 read 7670588 relations
- Mon Mar 15 16:26:14 2021 multiplying 7670588 relations
- Mon Mar 15 16:28:56 2021 multiply complete, coefficients have about 189.20 million bits
- Mon Mar 15 16:28:57 2021 initial square root is modulo 6166519
- Mon Mar 15 16:32:17 2021 sqrtTime: 461
- Mon Mar 15 16:32:17 2021 p75 factor: 317848117011204156242492444579232430116616203930212925730530140629381887143
- Mon Mar 15 16:32:17 2021 p135 factor: 859442618351426670517747242398612984488830961900230377825049696475160733855929173191593699737192768549744271523945621638414855871771053
- Mon Mar 15 16:32:17 2021 elapsed time 31:05:18
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement