#define _USE_MATH_DEFINES
#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<string>
#include<iomanip>
#include<numeric>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<random>
using namespace std;
typedef long long ll;
const int mod=998244353;
int main(){
	string sa,pa,xa,sb,pb,xb;
	cin>>sa>>pa>>xa>>sb>>pb>>xb;
	if(pa.size()!=pb.size())
		cout<<(pa.size()>pb.size()?sa:sb)<<endl;
	else if(pa!=pb)
		cout<<(pa>pb?sa:sb)<<endl;
	else
		cout<<-1<<endl;
}