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 x2 = sc.nextInt();
        int y2 = sc.nextInt();
        int ans = Math.max(x,y);
        if(x==y&&x2==y2&&x>x2){
            ans++;
        }
        System.out.println(ans);
    }
}