#include <bits/stdc++.h>
using namespace std;

int main() {
    string s, t;
    cin >> s >> t;
  
   sort(s.begin(),s.end());
  sort(t.begin(),t.end());
  reverse(t.begin(),t.end());
  
  if(s<t) cout << "Yes";
  else cout << "No";
}