#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>
//#include<bits/stdc++.h>


using namespace std;



int main(){
	
string n,m;
string p,q;
char y,s;
cin>>p>>n>>y;
cin>>q>>m>>s;
if(n>m)cout<<p<<endl;
else if(n<m)cout<<q<<endl;
else cout<<"-1"<<endl;
	return 0;

	}