#include <bits/stdc++.h>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;

int main(){
	string s[2], p[2], x[2];
	for(int i=0; i<2; i++) cin >> s[i] >> p[i] >> x[i];
	if(p[0].length()>p[1].length()){
		cout << s[0] << endl;
		return 0;
	}else if(p[0].length()<p[1].length()){
		cout << s[1] << endl;
		return 0;
	}else{
		for(int i=0; i<p[0].length(); i++){
			if(p[0][i]>p[1][i]){
				cout << s[0] << endl;
				return 0;
			}else if(p[0][i]<p[1][i]){
				cout << s[1] << endl;
				return 0;
			}
		}
	}
	cout << -1 << endl;
	return 0;
}