#include <bits/stdc++.h>

using namespace std;

int main()
{
    string sa, sb, pa, pb; char xa, xb;
    cin >> sa >> pa >> xa;
    cin >> sb >> pb >> xb;
    if (pa.size() > pb.size()) {
        cout << sa << endl;
    } else if (pb.size() > pa.size()) {
        cout << sb << endl;
    } else {
        cout << (pa > pb ? sa : pb > pa ? sb : "-1") << endl;
    }
}