#include <bits/stdc++.h>
namespace IO {
char buf[110];
}
template <typename T>
inline void qr(T &x) {
  register char ch = getchar(), lst = ' ';
  while ((ch > '9') || (ch < '0')) lst = ch, ch = getchar();
  while ((ch >= '0') && (ch <= '9'))
    x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
  if (lst == '-') x = -x;
}
template <typename T>
inline void qw(T x, const char aft, const bool pt) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  register int top = 0;
  do {
    IO::buf[++top] = x % 10 - '0';
  } while (x /= 10);
  while (top) putchar(IO::buf[top--]);
  if (pt) putchar(aft);
}
template <typename T>
inline T mmax(const T a, const T b) {
  return a > b ? a : b;
}
template <typename T>
inline T mmin(const T a, const T b) {
  return a < b ? a : b;
}
template <typename T>
inline T mabs(const T a) {
  return a < 0 ? -a : a;
}
template <typename T>
inline void mswap(T &a, T &b) {
  T _temp = a;
  a = b;
  b = _temp;
}
const int maxn = 100010;
int n;
int bk[maxn];
char MU[maxn];
int main() {
  qr(n);
  scanf("%s", MU + 1);
  std::sort(MU + 1, MU + 1 + n);
  printf("%s", MU + 1);
  return 0;
}
