func main()
	do cui@input()
	var sx: int :: cui@inputInt()
	var sy: int :: cui@inputInt()
	var gx: int :: cui@inputInt()
	var gy: int :: cui@inputInt()
	var ans: int :: (gx - sx).abs() + (gy - sy).abs()
	do cui@print("\{ans}\n")
end func