Timer

summon falling_block ~ ~1 ~ {Block:log,Time:1,Passengers:[{id:falling_block,Block:redstone_block,Time:1,Passengers:[{id:falling_block,Block:activator_rail,Time:1,Passengers:[{id:commandblock_minecart,Command:"kill @e[type=!Player,tag=ccp_pKSkrVTr]"},{id:commandblock_minecart,Command:gamerule commandBlockOutput false},{id:commandblock_minecart,Command:scoreboard objectives add Timer dummy},{id:commandblock_minecart,Command:scoreboard objectives setdisplay sidebar Timer},{id:commandblock_minecart,Command:setblock ~2 ~-3 ~0 repeating_command_block 5 0 {auto:1,Command:scoreboard players add @a Timer 1}},{id:commandblock_minecart,Command:setblock ~ ~ ~1 command_block 0 0 {Command:fill ~ ~-3 ~-1 ~ ~ ~ air}},{id:commandblock_minecart,Command:setblock ~ ~-1 ~1 redstone_block},{id:commandblock_minecart,Command:kill @e[type=commandblock_minecart,r=1]}]}]}]}