#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    string S1,S2;
    cin >> S1 >> S2;
    
    bool is_new = false;
    for ( int i = 0; i < 4; i+=2 ) {
        if ( S2[i] > S1[i] ) { is_new = true; break; }
    }
    
    cout << ( is_new ? "NO" : "YES" ) << endl;
    
    return 0;
}