#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"<<endl;
  else cout<<"No"<<endl;
  return(0);
}