Mine Shaft

print ("Length?")
l = io.read()
x = 1

function main()
	for i=1, l, 1 do
		turtle.dig()
		turtle.forward()
	end
			rightTurn()
end

function rightTurn()
	turtle.turnRight()
	turtle.dig()
	turtle.forward()
	turtle.turnRight()
		main2()
end

function main2()
	for i=1, l, 1 do
		turtle.dig()
		turtle.forward()
	end
			leftTurn()
end

function leftTurn()
	turtle.turnLeft()
	turtle.dig()
	turtle.forward()
	turtle.turnLeft()
		math()
end

function math()
	x=x+1
		if x == l then
			os.shutdown()
		elseif x ~= l then
			main()
		end
end