#include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
//#include "toollib.h"
#define INT_MAX 2147483647
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#pragma warning (disable:4018)

using namespace std;
typedef long long int lint;

//***** Main Program *****

int compare_large_number(string a, string b) {
	if (a.length() < b.length()) return 1;
	else if (a.length() > b.length()) return -1;
	else {
		int judge = 0;
		Loop(i, a.length()) {
			if (a[i] < b[i]) {
				judge = 1;
				break;
			}
			else if (a[i]>b[i]) {
				judge = -1;
				break;
			}
		}
		return judge;
	}
}

int main() {
	string Sa, Sb;
	string Pa, Pb;
	char Xa, Xb;
	cin >> Sa >> Pa >> Xa;
	cin >> Sb >> Pb >> Xb;
	int judge = compare_large_number(Pa, Pb);
	if (judge == -1) cout << Sa << endl;
	else if (judge == 1) cout << Sb << endl;
	else cout << -1 << endl;
	return 0;
}