import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s1 = sc.next(), p1 = sc.next(), x = sc.next();
		String s2 = sc.next(), p2 = sc.next(), y = sc.next();
		if(p1.length() > p2.length()){
			System.out.println(s1);
		} else if(p1.length() < p2.length()){
			System.out.println(s2);
		}else if(p1.compareTo(p2) > 0){
			System.out.println(s1);
		} else if(p1.compareTo(p2) < 0){
			System.out.println(s2);
		} else {
			System.out.println(-1);
		}
	}
}