#include <iostream>
#include <fstream>
using namespace std;
ifstream in("algsort.in");
ofstream out("algsort.out");
char a[500000];
int main()
{
    int n,i,j,aux;
    in>>n;
    for(i=1;i<=n;i++)
      in>>a[i];
    for(i=1;i<n;i++)
      for(j=i+1;j<=n;j++)
          if(a[i]>a[j])
              {
                    aux=a[i];
                    a[i]=a[j];
                    a[j]=aux;
              }
    for(i=1;i<=n;i++)
      out<<a[i];
    return 0;
}