import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String Sa = scan.next();
		String Pa = scan.next();
		String Xa = scan.next();
		String Sb = scan.next();
		String Pb = scan.next();

		String Xb = scan.next();
		if(Xa.equals(Xb)) {
		}
		scan.close();
		if(Pa.length() > Pb.length()) {
			System.out.println(Sa);
		}else if(Pa.length() < Pb.length()) {
			System.out.println(Sb);
		}else {
			for(int i = 0; i < Pa.length(); i++) {
				int a = Integer.parseInt(Pa.substring(i, i + 1));
				int b = Integer.parseInt(Pb.substring(i, i + 1));
				if(a > b) {
					System.out.println(Sa);
					System.exit(0);
				}else if(a < b) {
					System.out.println(Sb);
					System.exit(0);
				}
			}
		}
		System.out.println(-1);

	}
}