#include <bits/stdc++.h>
using namespace std;

int main() {
  string A, B, C, D, E, F;
  cin >> A >> B >> C >> D >> E >> F;
  if (B.size() > E.size()) cout << A << "\n";
  else if (B.size() < E.size()) cout << D << "\n";
  else cout << ((B > E) ? A : (B < E) ? D : "-1") << "\n";
}