#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  string a, b;
  cin >> a >> b;
  string ans = "YES";
  if (a < b) ans = "NO";
  cout << ans << endl;
  getchar();
}