#include <iostream>
using namespace std;

int main(){
    string s1,s2;
    long long p1 = 0;
    long long p2 = 0;
    char x1,x2;
    cin >> s1 >> p1 >> x1;
    cin >> s2 >> p2 >> x2;
    if(p1==p2){
        cout << "-1";
    }else if(p1 > p2){
        cout << s1;
    }else if(p1 < p2){
        cout << s2;
    }
    cout << "\n";
    return 0;
}