package main

import . "fmt"

func main() {
	var x, y, x2, y2 int
	Scan(&x,&y,&x2,&y2)
	switch {
		case x == 0 || y == 0:
			Println(x+y)
		case x == y && x2 == y2 && x > x2:
			Println(x+1)
		case x < y:
			Println(y)
		case x > y:
			Println(x)
		case x == y:
			Println(x)
	}
}