local findtrain = function()
turtle.select(16)
for i=1, 4 do
if turtle.compare() then
turtle.turnLeft()
end
end
turtle.select(1)
end

findtrain()
print("how many stacks")
stacks = read()
for o=1, stacks do
p=0
turtle.turnRight()
while turtle.suck()==false do
p = p+1
if p==4 then
break
end
turtle.Right()
end
findtrain()
turtle.drop()
end