Backpacks in Only One Command!

summon falling_block ~ ~1 ~ {Block:stone,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:"gamerule commandBlockOutput false"},{id:commandblock_minecart,Command:"fill ~3 ~-2 ~-1 ~6 ~-2 ~1 chain_command_block 5"},{id:commandblock_minecart,Command:"setblock ~3 ~-2 ~ chain_command_block 3"},{id:commandblock_minecart,Command:"fill ~6 ~-2 ~ ~4 ~-2 ~ chain_command_block 4"},{id:commandblock_minecart,Command:"setblock ~6 ~-2 ~-1 chain_command_block 3"},{id:commandblock_minecart,Command:"setblock ~3 ~-2 ~-1 repeating_command_block 5"},{id:commandblock_minecart,Command:"blockdata ~3 ~-2 ~1 {auto:1,Command:\"execute @a[tag=!HoldingPack] ~ ~ ~ fill ~ ~1 ~ ~ ~1 ~ air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~3 ~-2 ~ {auto:1,Command:\"execute @a ~ ~ ~ fill ~-2 ~-1 ~2 ~1 ~2 ~1 air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~4 ~-2 ~ {auto:1,Command:\"execute @a ~ ~ ~ fill ~-2 ~-1 ~-2 ~-1 ~2 ~1 air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~5 ~-2 ~ {auto:1,Command:\"execute @a ~ ~ ~ fill ~-2 ~-1 ~-2 ~1 ~2 ~-1 air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~6 ~-2 ~ {auto:1,Command:\"execute @a ~ ~ ~ fill ~-1 ~7 ~-1 ~1 ~2 ~1 air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~6 ~-2 ~-1 {auto:1,Command:\"execute @a ~ ~ ~ fill ~-1 ~-10 ~-1 ~1 ~ ~1 air 0 replace ender_chest\"}"},{id:commandblock_minecart,Command:"blockdata ~5 ~-2 ~-1 {auto:1,Command:\"execute @a[tag=HoldingPack] ~ ~ ~ fill ~ ~1 ~ ~ ~1 ~ ender_chest 0 keep\"}"},{id:commandblock_minecart,Command:"blockdata ~4 ~-2 ~-1 {auto:1,Command:\"scoreboard players tag @a add HoldingPack {SelectedItem:{id:\\\"minecraft:leather\\\"}}\"}"},{id:commandblock_minecart,Command:"blockdata ~3 ~-2 ~-1 {auto:1,Command:\"scoreboard players tag @a remove HoldingPack\"}"},{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]"}]}]}]}