#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;

int main(){
	string a,b,c,d;
	string pa,pb;
	cin >> a >> pa >> c;
	cin >> b >> pb >> d;
	if(pa.size() > pb.size()) cout << a << endl;
	else if(pb.size() > pa.size()) cout << b << endl;
	else if(pa.compare(pb) > 0) cout << a << endl;
	else if(pb.compare(pa) > 0) cout << b << endl;
	else cout << -1 << endl;	
	return 0;
}