#include <iostream>
using namespace std;

int main() {
string names[2]; string hensati[2]; string hoge;
for(int i=0;i<2;i++) {
cin >> names[i] >> hensati[i] >> hoge;
}
if(hensati[0].size()  < hensati[1].size()) {
cout << names[1] << endl;
}
else if(hensati[0].size() > hensati[1].size()) {
cout << names[0] << endl;
}
else if(hensati[0] == hensati[1]) {
cout << -1 << endl;
}
else {
cout << names[hensati[0] < hensati[1]] << endl;
}
return 0;
}