#include <bits/stdc++.h>
using namespace std;
string s1, t1, u1, s2, t2, u2;
int main() {
	cin >> s1 >> t1 >> u1;
	cin >> s2 >> t2 >> u2;
	if(t1.size() != t2.size()) cout << (t1.size() > t2.size() ? s1 : s2) << endl;
	else if(t1 != t2) cout << (t1 > t2 ? s1 : s2) << endl;
	else cout << -1 << endl;
	return 0;
}