import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		int y = sc.nextInt();
		int x1 = sc.nextInt();
		int y1 = sc.nextInt();
		if (x == y && x1 == y1) {
		    System.out.println(x + 1);
		} else {
		    System.out.println(Math.max(x, y));
		}
	}
}