#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

bool gt(const string &p1, const string &p2) {
  if (p1.size() != p2.size())
    p1.size() > p2.size();
  return p1 > p2;
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  string s1, s2, p1, p2, _;

  cin >> s1 >> p1 >> _;
  cin >> s2 >> p2 >> _;

  if (gt(p1, p2))
    cout << s1 << endl;
  else if (gt(p2, p1))
    cout << s2 << endl;
  else
    cout << -1 << endl;
  
  return 0;
}