#include<fstream.h>
#define dim 10000
char v[dim];
int main()
{
ifstream f("algsort.in");
ofstream g("algsort.out");
int n,i,man,j;
f>>n;
for (i=1;i<=n;i++)
f>>v[i];
for(i=1;i<=n;i++)
  for(j=1;j<=n;j++)
   if (v[i]>v[j])
       {man=v[i];
	v[i]=v[j];
	v[j]=man;}
  for(i=n;i>=1;i--)
  if(i!=i+1)
  g<<v[i];
  g<<"\n";




f.close();
g.close();
return 0;
}