#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";
  return 0;
}