#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<stdlib.h>
#include<vector>
#include<string>
#include<sstream>
#include<math.h>
using namespace std;


int main(){

  string s[2];
  string p[2];
  string x[2];

  cin >> s[0] >> p[0] >> x[0];
  cin >> s[1] >> p[1] >> x[1];

  if( p[0].size() > p[1].size() ){
    cout << s[0] << endl;
    return 0;
  }else if( p[0].size() < p[1].size() ){
    cout << s[1] << endl;
    return 0;
  }else{
    for(int i=0; i<p[0].size(); i++){
      if( p[0][i]-'0' > p[1][i]-'0' ){
        cout << s[0] << endl;
        return 0;
      }else if( p[0][i]-'0' < p[1][i]-'0' ){
        cout << s[1] << endl;
        return 0;
      }
    }
  }
  cout << -1 << endl;

  return 0;
}