#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;


int main() {
    string SA, PA, XA;
    string SB, PB, XB;
    cin >> SA >> PA >> XA;
    cin >> SB >> PB >> XB;

    string res = "-1";

    if (PA.size() > PB.size()) {
        res = SA;
    } else if (PA.size() < PB.size()) {
        res = SB;
    } else {

        for (int i = 0; i < PA.size(); ++i) {
            int a = PA[i] - '0';
            int b = PB[i] - '0';
            if (a > b) {
                res = SA;
            } else if (a < b) {
                res = SB;
            }
        }

    }

    cout << res << endl;
    return 0;
}