#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
using ll=long long;
using ld=long double;
ld pie=3.141592653589793;
ll mod=1000000007;
ld inf=10000999999999900;
int main(){
    vector<string>s(2),x(2);
    vector<string>p(2);
    for (ll i = 0; i < 2; i++)
    {
        cin >> s[i] >> p[i] >> x[i];
    }
    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;
    }
    
    
    if (p[0]>p[1])
    {
        cout << s[0] << endl;
    }else if (p[0]==p[1])
    {
        cout << -1 << endl;
    }else{
        cout << s[1] << endl;
    }
    
    
}