#include<iostream>
#include<cmath>
#include<string>

using namespace std;

#define WIN 1
#define DRAW 0
#define LOSE -1

int win_lose(string a,string b){
	if(a.size()>b.size()) return WIN;
	else if(a.size()<b.size()) return LOSE;
	for(int i=0;i<a.size();i++){
		if(a[i]<b[i]) return LOSE;
		else if(a[i]>b[i]) return WIN;
	}
	return DRAW;
}

int main(){

	string SA,SB,PA,PB,XA,XB;
	int res;

	cin>>SA>>PA>>XA;
	cin>>SB>>PB>>XB;

	res=win_lose(PA,PB);

	if(res==DRAW) cout<<"-1"<<endl;
	else if(res==WIN) cout<<SA<<endl;
	else cout<<SB<<endl;
}