#include<bits/stdc++.h>

using namespace std;
using ll = long long;

bool is_integer(double x){
    return floor(x) == x;
}

int main(){
    string sa,sb,pa,pb,xa,xb;

    cin >> sa >> pa >> xa;
    cin >> sb >> pb >> xb;

    auto comp = [=]() -> bool {
        int na = pa.size(),nb = pb.size();

        if(na > nb) return true;
        else if(na < nb) return false;
        else{
            bool res = true;
            for(int i=na;i >= 0;i--){
                if(pa[i] > pb[i]) res = true;
                else if(pa[i] < pb[i]) res = false;
                else continue;
            }
            return res;
        }
    };
    if(stoi(pa) == stoi(pb)) cout << -1 << endl;
    else cout << (comp() ? sa : sb) << endl;
}