#include <iostream>
using namespace std;
int main() {
	int poia,poib;
	char cha,chb;
	string stra,strb;
	cin>>stra>>poia>>cha;
	cin>>strb>>poib>>chb;
	if(poia==poib){
		cout<<"-1"<<endl;
	}else if(poia>poib){
		cout<<stra<<endl;
	}else{cout<<strb<<endl;}
	return 0;
}