import java.util.Scanner;

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