local currentInventorySlot = 1
local size = 0 + read()

function square( dimension )
  if dimension == 1 then
    turtle.placeDown()
  else
    dimension = dimension - 1
    for i = 1, 4 do
      for j = 1, dimension do
        turtle.forward()
        turtle.placeDown()
      end
      turtle.turnRight()
    end
  end
end

function checkInv()
  while turtle.getItemCount( currentInventorySlot ) == 0 do
    currentInventorySlot = currentInventorySlot + 1
    turtle.select( currentInventorySlot )
    if currentInventorySlot == 16 then
      turtle.select( 1 )
      currentInventorySlot = 1
    end
  end
end

turtle.select( 1 )
while size > 1 do
  checkInv()
  square(size)
  turtle.up()
  turtle.forward()
  turtle.turnRight()
  turtle.forward()
  turtle.turnLeft()
  size = size - 2
end
checkInv()
turtle.placeDown()