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.
import java.util.*; 
import java.math.*;
import java.io.*;
import java.text.DecimalFormat;
import java.math.BigInteger;
public class Main{
    //static int d=20;
    static long mod=1000000007 ;
    
    static ArrayList<ArrayList<Integer>> arr;
   // static long[] dp1,dp2;
    static int[] a;
    static int[] vis,num;
    static long max;
    static HashSet<String> hs;
    //static int flag,ans;
    static long max1,max2,ans1;
    
    static int flag=0;
    static int[] tin,tout,parent,level;
    static HashMap<Long,Integer> hm;
    static long[] dp1,dp2,dp3,dp4;
       
    public static void main(String[] args)  throws IOException {
        ///long start=System.currentTimeMillis();
        boolean online = false;
        String fileName = "B-small-attempt0.in";
        PrintWriter out; 
        if (online) {
            s.init(new FileInputStream(new File("Downloads/"+fileName)));
             out= new PrintWriter(new FileWriter(fileName + "out.txt"));
        }
         else {
            s.init(System.in);   
        
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
        }
        int n=s.ni();
        String a=s.ns();
        int[] ct=new int[26];
        for(int i=0;i<n;i++){
        	char ch=a.charAt(i);
        	ct[ch-'a']++;
        }
        StringBuilder sb=new StringBuilder();
        for(int i=0;i<26;i++){
        	while(ct[i]>0){
        		sb.append((char)(i+'a'));
        		ct[i]--;
        	}
        }
        out.println(sb.toString());

        out.close();        

    }
   
    

    public static void union(int[] a,int x,int y){
        int u=find(a,x);
        int v=find(a,y);
        a[v]=u;

    }
    public static int find(int[] a,int x){
        if(a[x]!=x){
            a[x]=find(a,a[x]);
        }
        return a[x];
    }
    public static int gcd(int a, int b){
            if (a == 0) return b;
            return gcd(b % a, a);
    }
        
    public static void cfs(ArrayList<HashSet<Integer>> arr,int c,int p,int g,int[] vis){
        vis[c]=1;
        if(g!=-1){
            if(!arr.get(c).contains(g)){
                flag=1;
                return;
            }
        }
        for(int x:arr.get(c)){
            if(x!=p && x!=g && vis[x]==0 ){
                cfs(arr,x,c,p,vis);
            }
        }

    }
                          //   public static void dfs(int u,int p){
//                            //       if(p>=0)
//                            //           tin[u]=tout[u]=tt++;
//                            //       if(p>=0)
//                            //           level[u]=level[p]+1;
//                            //       parent[u]=p;
//                            //       for(int x:arr.get(u)){
//                            //           if(x!=p){
//                            //               dfs(x,u);
//                            //               tout[u]=Math.max(tout[u],tout[x]);
//                            //           }
//                            //       }
//                            //       
//
//
 //   }
    public static int lca(int[][] p,int a,int b){
        if(level[a]<level[b]){
            int x=a;
            a=b;
            b=x;
        }
        int log=p[0].length;
        for(int i=log-1;i>=0;i--){
            if(1<<i<=level[a]-level[b]){
                a=p[a][i];
            }
        }
        if(a==b)
            return a;
        for(int i=log-1;i>=0;i--){
            if(p[a][i]!=p[b][i]){
                a=p[a][i];
                b=p[b][i];
            }
        }
        return p[a][0];

    }
    public static int[][] par(int[] parent){
        int n=arr.size();
        int[][] p=new int[n][17];
        for(int i=0;i<n;i++)
            p[i][0]=parent[i];
        for(int k=1;k<17;k++){
            for(int i=0;i<n;i++){
                if(p[i][k-1]>-1)
                    p[i][k]=p[p[i][k-1]][k-1];
                else
                    p[i][k]=-1;
            }
        }
        return p;
    }
    static class Edge implements Comparable<Edge>{
           int from;
            int to;
            long cost;
    
           public Edge(int from, int to, long weight) {
               this.from = from;
               this.to = to;
               this.cost= weight;
           }
           public int compareTo(Edge o){
                return (int)Math.signum(cost-o.cost); 
           }

    }                               
    static class Node {
        int start;
        int end;

        int cost;
        int updated;

        Node[] nodes;

        public Node(int start, int end) {
            this.start = start;
            this.end = end;

            if (start < end) {
                int[] pos = {start, (start + end) / 2, end};
                nodes = new Node[2];
                for (int i = 0; i < 2; i++) {
                    nodes[i] = new Node(pos[i] + i, pos[i + 1]);
                }
            }
        }

        public void update(int queryStart, int queryEnd, int value) {
            if (queryEnd < start || end < queryStart) {
                return;
            }

            if (queryStart <= start && end <= queryEnd) {
                cost += value;
                updated += value;
                return;
            }

            propagate();
            for (Node node: nodes) {
                node.update(queryStart, queryEnd, value);
            }
        }

        public int query(int pos) {
            if (pos < start || end < pos) {
                return 0;
            }

            if (start == end) {
                return cost;
            }

            propagate();
            int ans = 0;
            for (Node node: nodes) {
                ans = Math.max(ans, node.query(pos));
            }
            return ans;
        }

        public void propagate() {
            if (updated != 0 && start < end) {
                for (Node node: nodes) {
                    node.cost += updated;
                    node.updated += updated;
                }
                updated = 0;
            }
        }
    }
    public static double nthroot(int n, double A) {
        return nthroot(n, A, 0.0000001);
    }
    public static double nthroot(int n, double A, double p) {
        if(A < 0) {
            System.err.println("A < 0");// we handle only real positive numbers
            return -1;
        } else if(A == 0) {
            return 0;
        }
        double x_prev = A;
        double x = A / n;  // starting "guessed" value...
        while(Math.abs(x - x_prev) > p) {
            x_prev = x;
            x = ((n - 1.0) * x + A / Math.pow(x, n - 1.0)) / n;
        }
        return x;
    }
    
    static class item implements Comparable<item> {
        int from,to,cost;
        public item(int x,int y){
            from=x;
            to=y;
            
        }
        public int compareTo(item o){
            
            return  o.cost-cost;
        }
        
    }
   
    public static void dfs2(int c,int p,int[] a){
        //System.out.println(c+" "+p);
       
        
        

    }
//public static void dfs(int x,int[] vis,Stack<Integer> st){
    //    vis[x]=1;
    //    ArrayList<Integer> arr2=arr.get(x);
    //    Collections.sort(arr2);
    //    for(int i=arr2.size()-1;i>=0;i--){
    //        int z=arr2.get(i);
    //        if(vis[z]==0)
    //            dfs(z,vis,st);
    //    }
    //    st.push(x);
//
    //}
    public static long gcd2(long a, long b){
            if (a == 0) return b;
            return gcd2(b % a, a);
    }
        
    public static boolean check(long x){
        if(x%4==0 || x%7==0 || x%11==0)
            return true;
        if(x<4 || x<7 || x<11)
            return false;
        if(x%2==0){
            return check(x/2);
        }
        else
            return check(x/2) && check((x+1)/2);
    }
    public static int angle(int x1,int x2,int x3,int y1,int y2,int y3){
        long val=(y2-y1)*1L*(x3-x2)-(y3-y2)*1L*(x2-x1);
        if(val<0)
            return 1;
        else if(val>0)
            return -1;
        else
            return 0;
    }
    
    static class BIT{
    
        int N;
        long tree[];
        
        BIT(int N){
            this.N = N;
            tree = new long[N + 1];
        }
        
        void update(int idx,long val){
            while(idx <= N){
                tree[idx]+=val;
                idx += (idx & -idx);
            }
        }
        
        long query(int l,int r){
            if(l == 1)
                return read(r);
            else
                return read(r) - read(l-1);
        }
        
        long read(int idx){
            long sum = 0;
            while(idx > 0){
                sum += tree[idx];
                idx -= (idx & -idx);
            }
            return sum;
        }
    }
    public static boolean pal(String a){
        int i=0;
        int j=a.length()-1;
        while(i<j){
            if(a.charAt(i)!=a.charAt(j)){
                return false;
            }
            i++;
            j--;
        }
        return true;
            
    }
    public static long find(long n,long k){
        if(n==2){
            if(k==1 || k==3)
                return 1;
            else
                return 2;
        }
        long t=pow2(2,n,mod)-1;
        long z=(t+1)/2;
        if(k==z)
            return n;
        if(k<z)
            return find(n-1,k);
        else
            return find(n-1,k-z);
    }
    public static long pow2(long a,long b,long mod){
            
            long ans=1;
           // long z=b;
            while(b>0){
               
                if(b%2==1)
                    ans=(a*ans)%mod;
                a=(a*a)%mod;
                b/=2;
            }
          
            return  ans;
    }
     public static long pow3(long a,long b){
            
            long ans=1;
           // long z=b;
            while(b>0){
               
                if(b%2==1)
                    ans=(a*ans);
                a=(a*a);
                b/=2;
            }
          
            return  ans;
    }
    public static long fib(long n){
        long[][]    f=new long[][]{{1L,1L},{1L,0}};
        if(n==0)
            return 0;
        f=arrpow(f,n-1);
        return f[0][0];
    }
    public static long[][] arrpow(long[][] a,long b){
       
            int n=a.length;
          //  long z=b;
            long[][] ans=new long[n][n];
            for(int i=0;i<n;i++)
                ans[i][i]=1L;
            while(b>0){
                
                if(b%2==1)
                    ans=mul(a,ans);
                a=mul(a,a);
                b/=2;
            }
            
            return  ans;
    }
    public static long[][] mul(long[][] a,long[][] b){
        int n=a.length;
        int m=b[0].length;
        long[][] ans=new long[n][m];
        if(n==2 && m==2 && b.length==2){
            ans[0][0]=((a[0][0]*b[0][0])%mod+(a[0][1]*b[1][0]))%mod;
            ans[0][1]=((a[0][0]*b[0][1])%mod+(a[0][1]*b[1][1]))%mod;
            ans[1][0]=((a[1][0]*b[0][0])%mod+(a[1][1]*b[1][0]))%mod;
            ans[1][1]=((a[1][1]*b[1][1])%mod+(a[1][0]*b[0][1]))%mod;
            return ans;

        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                for(int k=0;k<b.length;k++){
                    ans[i][j]=(ans[i][j]+(a[i][k]*b[k][j])%mod)%mod;
                }
            }
        }
        return ans; 
    }
     static class name implements Comparable<name> {
        long l,b,h;
        public name(long   x,long y,long z){
            {
                l=x;
                b=y;        
            }
            
            
            h=z;
        }
        public int compareTo(name o){
            return -(int)(l*b-o.l*o.b);
        }
        
    }
    public static class s {
        static BufferedReader reader;
        static StringTokenizer tokenizer;
    
        /** call this method to initialize reader for InputStream */
        static void init(InputStream input) {
            reader = new BufferedReader(
                        new InputStreamReader(input) );
            tokenizer = new StringTokenizer("");
        }   
    
        /** get next word */
        static String ns() throws IOException {
            while ( ! tokenizer.hasMoreTokens() ) {
                //TODO add check for eof if necessary
                tokenizer = new StringTokenizer(
                    reader.readLine() );
            }
            return tokenizer.nextToken();
        }
    
        static int ni() throws IOException {
            return Integer.parseInt( ns() );
        }
    
        static double nd() throws IOException {
            return Double.parseDouble( ns() );
        }
        static long nl() throws IOException {
            return Long.parseLong( ns() );
        }
    }
}   
