import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int x = scan.nextInt();
		int y = scan.nextInt();
		int x2 = scan.nextInt();
		int y2 = scan.nextInt();
		scan.close();
		if(x == y && x2 == y2 && x2 < x) {
			int ans = x + 1;
			System.out.println(ans);
		}else {
			int ans =  Math.max(x, y);
			System.out.println(ans);
		}
	}
}