import java.util.Scanner;

public class Main{
	public static void main(String args[]){
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()){
			String a=sc.next();	String pa=sc.next(); sc.next();
			String b=sc.next(); String pb=sc.next(); sc.next();
			if(pa.compareTo(pb)<0) System.out.println(b);
			else if(pa.compareTo(pb)>0) System.out.println(a);
			else System.out.println(-1);
		}
	}
}