#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cctype>
#include<cstdlib>
#include<algorithm>
#include<bitset>
#include<vector>
#include<list>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<sstream>
#include<fstream>
#include<iomanip>
#include<ctime>
#include<complex>
#include<functional>
#include<climits>
#include<cassert>
#include<iterator>
using namespace std;
vector<pair<string, string> > v;
bool cmp(pair<string, string> a, pair<string, string> b){
	if (a.first == b.first){
		puts("-1");
		exit(0);
	}
	if (a.first.size() != b.first.size()){
		if (a.first.size() > b.first.size()){
			cout << a.second << endl;
		}
		else{
			cout << b.second << endl;
		}
		exit(0);
	}
	if (a.first < b.first){
		cout << b.second << endl;
	}
	else{
		cout << a.second << endl;
	}
	exit(0);
}
int main(){
	for (int i = 0; i < 2; i++){
		string a;
		string b;
		char c;
		cin >> a >> b >> c;
		v.push_back(make_pair(b, a));
	}
	//sort(v.begin(), v.end(), cmp);
	return 0;
}