#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	string s[2],t;
	string a[2];
	for (int i = 0; i < 2; i++) {
		cin >> s[i] >> a[i] >> t;
	}

	string win = "-1";
	int i=0;
	bool flag = true;
	if (a[0].size() > a[1].size()) {
		flag = false;
		win = s[0];
	}
	else if (a[0].size() < a[1].size()) {
		flag = false;
		win = s[1];
	}
	while (flag) {
		if (a[0][i] > a[1][i]) {
			flag = false;
			win = s[0];
		}
		else if (a[0][i] < a[1][i]) {
			flag = false;
			win = s[1];
		}
		if (i == a[0].size()) {
			break;
		}
		i++;
	}
	cout << win << endl;

	return 0;
}