#include <iostream>
using namespace std;

int main(){
    string name1,name2,p1,p2,ans;
    char c;

    cin >> name1 >> p1 >> c;
    cin >> name2 >> p2 >> c;
    if (p1.length() < p2.length())
        ans = name2;
    else if (p1.length() > p2.length())
        ans = name1;
    else if (p1 < p2)
        ans = name2;
    else if (p1 > p2)
        ans = name1;
    else
        ans = "-1";
    cout << ans << endl;
    return 0;
}