#include <bits/stdc++.h>

using namespace std;


int main() {
  string s1, s2, p1, p2, x1, x2;
  cin >> s1 >> p1 >> x1 >> s2 >> p2 >> x2;

  if (p1.size() > p2.size()) {
    cout << s1 << endl;
  } else if (p2.size() > p1.size()) {
    cout << s2 << endl;
  } else {
    if (p1 > p2) {
      cout << s1 << endl;
    } else if (p2 > p1) {
      cout << s2 << endl;
    } else {
      puts("-1");
    }
  }
  return 0;
}