turtle.select(1)
turtle.place()
while turtle.getItemCount(1) > 0 do
  turtle.select(2)
  if turtle.compare() then
    turtle.dig()
    turtle.select(1)
    turtle.place()
  else
    turtle.select(16)
    if turtle.compare() then
      turtle.forward()
      turtle.select(15)
      turtle.dig()
      turtle.back()
      turtle.dig()
      turtle.select(1)
      turtle.place()
    end
  end
end
