Treecapitator farm

function main()
  turtle.select(1)
if turtle.compare() then
  redstone.setOutput("left", true)
  sleep(15)
  redstone.setOutput("left", false)
  turtle.up()
  turtle.select(2)
  turtle.forward()
  turtle.placeDown()
  turtle.turnLeft()
  turtle.forward()
  turtle.placeDown()
  turtle.turnRight()
  turtle.forward()
  turtle.placeDown()
  turtle.turnRight()
  turtle.forward()
  turtle.placeDown()
  turtle.turnRight()
  turtle.forward()
  turtle.forward()
  turtle.down()

  turtle.select(1)
  a = turtle.getItemCount(1) - 1
  if a == -1 then
    a = 0
  end
  if a == 0 then
    a = 0
  end
  turtle.drop(a)

  turtle.select(2)
  b = turtle.getItemCount(2) - 1
  if b == -1 then
    b = 0
  end
  if b == 0 then
    b = 0
  end
  turtle.drop(b)

  turtle.select(3)
  turtle.drop()

  turtle.turnLeft()
  turtle.turnLeft()

end
sleep(120)
turtle.suckUp()
main()
end

main()