#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
int const lmt = 1e5 + 5;
long long int a[26];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int n;
  cin >> n;
  string second, ans = "";
  cin >> second;
  sort((second).begin(), (second).end());
  cout << second << "\n";
  return 0;
  for (int i = 0; i <= n - 1; i += 1) {
    a[second[i] - 'a']++;
  }
  for (int i = 0; i <= 26 - 1; i += 1) {
    if (a[i] % 2 == 1) {
      ans += char(i + 'a');
      a[i]--;
      break;
    }
  }
  for (int i = 0; i <= 26 - 1; i += 1) {
    if (a[i] > 1) {
      ans = char(i + 'a') + ans + char(i + 'a');
      a[i] -= 2;
      i--;
    }
  }
  for (int i = 0; i <= 26 - 1; i += 1) {
    if (a[i]) ans += char(i + 'a');
  }
  cout << ans << "\n";
}
