A non-empty string is called palindrome, if it reads the same from the left to the right and from the right to the left. For example, "abcba", "a", and "abba" are palindromes, while "abab" and "xy" are not.

A string is called a substring of another string, if it can be obtained from that string by dropping some (possibly zero) number of characters from the beginning and from the end of it. For example, "abc", "ab", and "c" are substrings of the string "abc", while "ac" and "d" are not.

Let's define a palindromic count of the string as the number of its substrings that are palindromes. For example, the palindromic count of the string "aaa" is 6 because all its substrings are palindromes, and the palindromic count of the string "abc" is 3 because only its substrings of length 1 are palindromes.

You are given a string s. You can arbitrarily rearrange its characters. You goal is to obtain a string with the maximum possible value of palindromic count.

Input

The first line contains an integer n (1 ≤ n ≤ 100 000) — the length of string s.

The second line contains string s that consists of exactly n lowercase characters of Latin alphabet.

Output

Print string t, which consists of the same set of characters (and each characters appears exactly the same number of times) as string s. Moreover, t should have the maximum possible value of palindromic count among all such strings strings.

If there are multiple such strings, print any of them.

Examples

Input

5
oolol


Output

ololo


Input

16
gagadbcgghhchbdf


Output

abccbaghghghgdfd

Note

In the first example, string "ololo" has 9 palindromic substrings: "o", "l", "o", "l", "o", "olo", "lol", "olo", "ololo". Note, that even though some substrings coincide, they are counted as many times as they appear in the resulting string.

In the second example, the palindromic count of string "abccbaghghghgdfd" is 29.
/*
 ~/BAU/ACM-ICPC/Teams/Rampage/MMZA
 ~/sudo apt-get verdict Accepted
 practice...
*/
//package javaapplication1;

//import java.util.Scanner;


import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;

public class Main {
    static final int Mod=(int)1e9+7;
    static final int N=(int)2e5+5;
    public static void main(String[] args) throws IOException {
       // Reader.init(System.in);
        //Scanner in=new Scanner(new FileInputStream("input.txt"));
        FastReader in=new FastReader();
        //in=new FileReader("input.txt");
        //PrintWriter out=new PrintWriter(new FileOutputStream("output.txt"));
        PrintWriter out=new PrintWriter(System.out);           
        Main ob=new Main();
        int n=in.nextInt();
        String s=in.next();
        String res=sort(s);
        out.println(res);
        out.close();
    }
    static int[] reverse(int [] arr){
        ArrayList<Integer> temp=new ArrayList();
        for(int i=0;i<arr.length;i++)
            temp.add(arr[i]);
        Collections.reverse(temp);
        for(int i=0;i<temp.size();i++)
            arr[i]=temp.get(i);
        return arr;
    }
    static String reverse(String s){
        String temp="";
        for(int i=s.length()-1;i>=0;i--)
            temp+=s.charAt(i);
        return temp;
    }
    static String sort(String inputString) 
    { 
        ArrayList<Character> arr=new ArrayList();
        for(int i=0;i<inputString.length();i++)
            arr.add(inputString.charAt(i));
        Collections.sort(arr);
        StringBuilder sb=new StringBuilder();
        for(int i=0;i<arr.size();i++)
            sb.append(arr.get(i));
        
        return sb.toString(); 
    } 
     
    static boolean next_permutation(int[] p, int len) {
        int a = len - 2;
        while (a >= 0 && p[a] >= p[a + 1]) {
            a--;
        }

        if (a == -1) {
            return false;
        }

        int b = len - 1;
        while (p[b] <= p[a]) {
            b--;
        }

        p[a] += p[b];
        p[b] = p[a] - p[b];
        p[a] -= p[b];

        for (int i = a + 1, j = len - 1; i < j; i++, j--) {
            p[i] += p[j];
            p[j] = p[i] - p[j];
            p[i] -= p[j];
        }

        return true;
    }
    static int lower_bound(ArrayList<Integer> arr,int key) {
        int len = arr.size();
        int lo = 0;
        int hi = len-1;
        int mid = (lo + hi)/2;
        while (true) {
            int cmp = (arr.get(mid)==key?1:0);
            if (cmp == 0 || cmp > 0) {
                hi = mid-1;
                if (hi < lo)
                    return mid;
            } else {
                lo = mid+1;
                if (hi < lo)
                    return mid<len-1?mid+1:-1;
            }
            mid = (lo + hi)/2;
        }
    }
    static int upper_bound(ArrayList<Integer> arr, int key) {
        int len = arr.size();
        int lo = 0;
        int hi = len-1;
        int mid = (lo + hi)/2;
        while (true) {
            int cmp = (arr.get(mid)==key?1:0);
            if (cmp == 0 || cmp < 0) {
                lo = mid+1;
                if (hi < lo)
                    return mid<len-1?mid+1:-1;
            } else {
                hi = mid-1;
                if (hi < lo)
                    return mid;
            }
            mid = (lo + hi)/2;
        }
    }
    static int gcd(int a,int b){
        return b==0?a:gcd(b,a%b);
    } 
    static double dot(Point p,Point q){
        return (p.x*q.x+p.y*q.y);
    }
    static double cross(Point p,Point q){
        return (p.x*q.y-p.y*q.x);
    }
    static Point computeLineIntersection(Point a,Point b,Point c,Point d){
        b=b.sub(a);d=c.sub(d);c=c.sub(a);
        return a.add(b.mulCon(cross(c,d)).devideCon(cross(b,d)));
    }
   static class FastReader 
        { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
  
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
  
}
class Reader {

    static BufferedReader reader;
    static StringTokenizer tokenizer;

    static void init(InputStream input) throws UnsupportedEncodingException {
        reader = new BufferedReader(
                new InputStreamReader(input, "UTF-8"));
        tokenizer = new StringTokenizer("");
    }

    static void init(String url) throws FileNotFoundException {
        reader = new BufferedReader(new FileReader(url));
        tokenizer = new StringTokenizer("");
    }

    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                    reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static String nextLine() throws IOException {
        return reader.readLine();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(next());
    }
}
class Point{    
    double x,y;
    Point(double _x,double _y){
        x=_x;
        y=_y;
    }
    Point add(final Point p){
        return new Point(x+p.x,y+p.y);
    }
    Point sub(final Point p){
        return new Point(x-p.x,y-p.y);
    }
    Point mulCon(final double c){
        return new Point(c*x,c*y);
    }
    Point devideCon(final double c){
        return new Point(x/c,y/c);
    }
}
class  pair implements Comparator<pair>{
    int first,second;
    pair(){}
    pair(int a,int b){
        first = a;
        second = b;
    }
   /* pair(pair a,pair b){
        first = a;
        second = b;
    }*/
    @Override 
    public int compare(pair a,pair b){
        return (a.first-b.first);
    }
}
