#include "bits/stdc++.h"
using namespace std;

int yurufuwa(string X, string Y) {
	if (X.size() > Y.size()) return 1;
	if (X.size() < Y.size()) return -1;
	for (int i = 0; i < X.size(); i++) {
		if (X[i] > Y[i]) return 1;
		if (X[i] < Y[i]) return -1;
	}
	return 0;
}

int main() {
	string SA, PA, XA, SB, PB, XB;
	cin >> SA >> PA >> XA >> SB >> PB >> XB;
	if (yurufuwa(PA, PB) == 1) cout << SA << endl;
	else if (yurufuwa(PA, PB) == -1) cout << SB << endl;
	else cout << -1 << endl;
}