#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()
#define RALL(x) (x).rbegin(),(x).rend()
#define REP(i,a,n) for(int i = (a);i < (n);i++)
#define PI 3.14159265359
#define MOD 1000000007

using namespace std;

int main(){
    string sa,sb,xa,xb,pa,pb,ans;
    cin >> sa >> pa >> xa >> sb >> pb >> xb;
    if(pa.length() > pb.length())ans = sa;
    else if(pa.length() < pb.length())ans = sb;
    else{
        REP(i, 0, pa.length()){
            if(pa[i]-'0' > pb[i]-'0'){
                ans = sa;
                break;
            }
            if(pa[i]-'0' < pb[i]-'0'){
                ans = sb;
                break;
            }
            else ans = "-1";
        }
    }
    cout << ans << endl;
    return 0;
}