#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#include <stack>
#include <array>
#include <fstream>

#define REP(i,n) for(int (i) = 0;(i) < (n) ; ++(i))
#define REPA(a,i,n) for(int (i) = (a) ; (i) < (n) ; ++(i))
#if defined(_MSC_VER)||__cplusplus > 199711L
#define AUTO(r,v) auto r = (v)
#else
#define AUTO(r,v) typeof(v) r = (v)
#endif
#define ALL(c) (c).begin() , (c).end()
#define EACH(it,c) for(AUTO(it,(c).begin());it != (c).end();++it)
#define LL long long
#define int LL
#define INF  99999999
#define DEV 1000000007
#define QUICK_CIN ios::sync_with_stdio(false); cin.tie(0);
using namespace std;

string a, b;

string ai, bi;

char ac, bc;
signed main()
{
	QUICK_CIN;
	//ifstream cin("debug.txt");
	//ofstream cout("result.txt");

	cin >> a >> ai >> ac >> b >> bi >> bc;

	if (ai.length() > bi.length()){
		cout << a << endl;
	}
	else if (ai.length() < bi.length()){
		cout << b << endl;
	}
	else{
		if (ai> bi){
			cout << a << endl;
		}
		else if (ai < bi){
			cout << b << endl;
		}
		else{
			cout << -1 << endl;
		}
	}

	return 0;
}