#include <bits/stdc++.h>

using namespace std;

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

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

  string s1, s2;
  int p1, p2;
  char _;

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

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