#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <numeric>
#define rep(x, to) for (int x = 0; x < (to); x++)
#define REP(x, a, to) for (int x = (a); x < (to); x++)
#define foreach(itr, x) for (typeof((x).begin()) itr = (x).begin(); itr != (x).end(); itr++)

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;
typedef pair<long, long> PLL;

string sa, pa, xa;
string sb, pb, xb;

int comp(string x, string y) {
	if (x.size() > y.size()) {
		return 1;
	} else if (x.size() < y.size()) {
		return -1;
	} else {
		rep(i, x.size()) {
			if (x[i] > y[i]) return 1;
			else if (x[i] < y[i]) return -1;
		}
	}
	return 0;
}

int main() {
	cin >> sa >> pa >> xa;
	cin >> sb >> pb >> xb;
	int res = comp(pa, pb);
	if (res > 0) {
		cout << sa << endl;
	} else if (res < 0) {
		cout << sb << endl;
	} else {
		cout << -1 << endl;
	}
	return 0;
}