input:
./PA5 test.txt 1
first clustering similarity: [depth_1_0000003.pgm] & [depth_1_sizechange.pgm] = 0.994946

second clustering similarity: [depth_1_0000003.pgm, depth_1_sizechange.pgm] & [size_1_0000004.pgm] = 0.989676

third clustering similarity: [depth_1_0000003.pgm, depth_1_sizechange.pgm, size_1_0000004.pgm] & [size_1_0001521.pgm] = 0.719633

output:
depth_1_0000003.pgm depth_1_sizechange.pgm depth_1_0000004.pgm depth_1_0001521.pgm