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

int s1, s2;
string p1, p2, s;
void input() { cin >> p1 >> s1 >> s >> p2 >> s2 >> s; }
void solve() {
  cout << ((s1 == s2) ? ("-1") : ((s1 > s2) ? (p1) : (p2))) << endl;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  input();
  solve();
}