import java.util.Scanner;

public class Main_yukicoder208 {
	
	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 ret = Math.max(x,  y);
		if (x == y && x2 == y2 && x2 < x) {
			ret++;
		}
		
		System.out.println(ret);
		
		sc.close();
	}
}