#include<bits/stdc++.h>
#define itsmdshahin		  ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define ll                long long
#define MX				  1000006
const int N = 100100;
using namespace std;
vector<ll>g[N];
int main()
{
    itsmdshahin;
    ll n,z=0;
    cin >> n;
    vector<ll>a;
    string t="abcdefghijklmnopqrstuvwxyz",s;cin >> s;
    for(int j=0;j<s.size();j++){
      for(int i=t.size()-1;i>=0;i--){
         if(s[j]==t[i]){
            a.push_back(i);
         }
      }
    }
    reverse(t.begin(),t.end());
    for(int j=0;j<a.size();j++){
      for(int i=0;i<t.size();i++){
         if(a[j]==i){
            cout << t[i];
         }
      }
    }
    cout << endl;

}