#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
#include <cctype>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <set>
#include <map>
#include <list>
#include <stdio.h>
#include <string.h>
#include <cstdlib>
#include <math.h>
#include <bitset>
#include <iterator>
#include <iomanip>
#include <sstream>
#include <numeric>
#define INF 2000000000
using namespace std;
int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
#define sym cout<<"---------"<<endl;
#define ll long long
#define PL pair<long long, long long>
#define P pair<int,int>
#define mk make_pair
#define en endl
#define WHITE 0
#define BLACK 2
#define GRAY 1
#define RE return 0
#define int ll


signed main(){
  string s,t;
  string s_n,t_n;
  char x,y;
  cin>>s>>s_n>>x;
  cin>>t>>t_n>>y;
  if(s_n.size()>t_n.size()) cout<<s<<en;
  else if(s_n.size()<t_n.size()) cout<<t<<en;
  else{
    for(int i=0; i<s_n.size(); i++){
      if(s_n[i]>t_n[i]) { cout<<s<<en; RE;}
      else if(s_n[i]<t_n[i]) {cout<<t<<en; RE;}
    }
    cout<<-1<<en;
  }
}