local distance = ...
if distance ~= nil and turtle.getFuelLevel() > (distance*2 + 150) then
    distance = tonumber(distance)
    for i = 1, distance do
        turtle.forward()
        while not turtle.forward() do
        turtle.dig()
        turtle.digUp()
        end
    end
    turtle.turnLeft()
    turtle.turnLeft()
    for i = 1, distance do
        turtle.forward()
    end
else
    print("add a valid distance or input more coal.")
end