#include "bits/stdc++.h"
using namespace std;
using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<ll, ll> P;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const long long mod = 1e9 + 7;

ll gcd(ll a, ll b) {
	return b ? gcd(b, a % b) : a;
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

int main() {
	string sa, pa, xa;
	cin >> sa >> pa >> xa;
	string sb, pb, xb;
	cin >> sb >> pb >> xb;
	
	ll a = pa.size();
	ll b = pb.size();

	if (a == b) {
		if (pa > pb) {
			cout << sa << endl;
		} else if (pa < pb){
			cout << sb << endl;
		} else {
			cout << -1 << endl;
		}
	} else if (a > b) {
		cout << sa << endl;
	} else {
		cout << sb << endl;
	}
}