#include <bits/stdc++.h>
using namespace std;
long long int isPowerOfTwo(long long int n) {
  if (n == 0) return 1;
  return (ceil(log2(n)) == floor(log2(n)));
}
int main() {
  long long int t, n, i, j, l, flag, flag1, count, count1, count2, count3,
      count4, sum, max1, max2, m, c1, c2, temp, suma, sumb;
  long long int f, e, c, d;
  long long int k;
  long long int a[300001], b[1001][1001], a1[300001];
  vector<long long int> v1, v2, v;
  string s1, s2, s;
  for (i = 0; i < 300001; i++) a1[i] = 0;
  count = 0, flag = -1, flag1 = 0, sum = 0, max1 = 0, max2 = 0, c1 = 0, c2 = 0,
  temp = 0, suma = 0, sumb = 0, count1 = 0, count2 = 0, count3 = 0, count4 = 0;
  long long int max3 = 0, max4 = 0, ans = 0, pro = 1, mina = 999999999, q, r;
  cin >> n;
  cin >> s;
  sort(s.begin(), s.end());
  cout << s;
  return 0;
}
