#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<map>
#include<vector>
using namespace std;
typedef long long int ll;

int main(){

  string Sa, Sb, Pa, Pb, Xa, Xb;
  cin >> Sa >> Pa >> Xa >> Sb >> Pb >> Xb;
  if(Pa.size()>Pb.size()){
    cout << Sa << endl;
  } else if(Pa.size()<Pb.size()){
    cout << Sb << endl;
  } else {
    for(int i=0; i<Pa.size(); i++){
      if(Pa[i]>Pb[i]){
        cout << Sa << endl;
        return 0;
      } else if(Pa[i]<Pb[i]){
        cout << Sb << endl;
        return 0;
      }
    }
    cout << -1 << endl;
  }
  

  return 0;
}