#include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#define rep(i,n) for(int i=0;i<n;i++)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define LL long long
#define mass 1000000007
using namespace std;


int main(){
	
	char sa[110];
	char sb[110];
	char pa[10010];
	char pb[10010];
	char xa,xb;

	cin>>sa>>pa>>xa;
	cin>>sb>>pb>>xb;

	//cout<<sa<<pa<<xa<<endl;
	//cout<<sb<<pb<<xb<<endl;
	int ca=0,cb=0;
	rep(i,10010){
		if( int(pa[i]) !=0 ){
			ca++;
		}else{
			break;
		}
	}
	rep(i,10010){
		if( int(pb[i]) !=0 ){
			cb++;
		}else{
			break;
		}
	}
	
	if(ca>cb){
		cout<<sa<<endl;
		return 0;
	}else if(cb>ca){
		cout<<sb<<endl;
		return 0;
	}

	rep(i,ca){
		if(pa[i]>pb[i]){
			cout<<sa<<endl;
			return 0;
		}else if(pa[i]<pb[i]){
			cout<<sb<<endl;
			return 0;
		}
	}
	cout<<-1<<endl;

	return 0;
	

}