local size= tonumber(read())
turtle.select(1)
slot = 1
for i=1, (size^2)/2 do
	for j=1, size do
		if not turtle.detectDown() then
			if turtle.getItemCount(slot) == 0 then
			else
				slot = slot+1
				turtle.select(slot)
			end
			turtle.placeDown()
			turtle.forward()
		else
			turtle.forward()
		end
	end
	turtle.turnLeft()
	turtle.forward()
	turtle.turnLeft()
	for j=1, size do
		if not turtle.detectDown() then
			if turtle.getItemCount(slot) == 0 then
			else
				slot = slot+1
				turtle.select(slot)
			end
			turtle.placeDown()
			turtle.forward()
		else
			turtle.forward()
		end
	end
	turtle.turnRight()
	turtle.forward()
	turtle.turnRight()
end