#include <cstdio>
#include <iostream>
#include <cstring>

using namespace std ;

string a, b, A, B ;

int main ( void ) {
    cin >> a ;
    cin >> b ;
    for ( int i = a.length () -1 ; i >= 0 ; --i )
        A += a [ i ] ;
    for ( int i = b.length () -1 ; i >= 0 ; --i )
        B += b [ i ] ;
    cout << max ( A, B ) << endl ;
    return 0 ;
}