#include <bits/stdc++.h>

using namespace std;
const int N = 110;
char a[N];
int main() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    sort(a + 1, a + 1 + n);

    for (int i = 1; i <= n; i++) cout << a[i];
    return 0;
}