#include <bits/stdc++.h>   using namespace std;   const int N = 200 + 10;   int main() {     int n, arr[N];     char f;     char ch[N];     scanf( %d , &n);     cin >> ch;     n = 2 * n;     for (int i = 0; i < n; i++) arr[i] = ch[i] -  0 ;     sort(arr, arr + n / 2);     sort(arr + n / 2, arr + n);     bool a = false, b = false;     for (int i = 0; i < n / 2; i++) {       if (arr[i] >= arr[n / 2 + i]) a = true;       if (arr[i] <= arr[n / 2 + i]) b = true;     }     if (a && b)       cout <<  NO ;     else       cout <<  YES ;     return 0;   }   