#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
using namespace std;
bool prime(long long int n) {
  if (n < 2) return false;
  if (n < 4) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (long long int i = 5; i <= sqrt(n); i += 6) {
    if (n % (i) == 0 || n % (i + 2) == 0) return false;
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  {
    long long int n, i;
    cin >> n;
    string s;
    cin >> s;
    sort((s).begin(), (s).end());
    cout << s;
    cout << '\n';
  }
  return 0;
}
