import java.math.BigInteger;
import java.util.*;
class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String A = sc.next();
		BigInteger a = new BigInteger(sc.next());
		String X = sc.next();
		String B = sc.next();
		BigInteger b = new BigInteger(sc.next());
		X = sc.next();
		
		if(a.compareTo(b) == 1) {
			System.out.println(A);
		}
		else if(a.compareTo(b) == -1) {
			System.out.println(B);
		}
		else {
			System.out.println(-1);
		}
		
		
		
		
		
		
	}
}