Appleman has n cards. Each card has an uppercase letter written on it. Toastman must choose k cards from Appleman's cards. Then Appleman should give Toastman some coins depending on the chosen cards. Formally, for each Toastman's card i you should calculate how much Toastman's cards have the letter equal to letter on ith, then sum up all these quantities, such a number of coins Appleman should give to Toastman.

Given the description of Appleman's cards. What is the maximum number of coins Toastman can get?

Input

The first line contains two integers n and k (1 ≤ k ≤ n ≤ 105). The next line contains n uppercase letters without spaces — the i-th letter describes the i-th card of the Appleman.

Output

Print a single integer – the answer to the problem.

Examples

Input

15 10
DZFDFZDFDDDDDDF


Output

82


Input

6 4
YJSNPI


Output

4

Note

In the first test example Toastman can choose nine cards with letter D and one additional card with any letter. For each card with D he will get 9 coins and for the additional card he will get 1 coin.
import javafx.util.Pair;

import java.io.*;
import java.sql.Array;
import java.util.*;
public class test {
    long max = 0;
    long max1=0;
    boolean visited[];
    PrintStream out = System.out;
    int sign[]={1,0,-1,0,0,1,0,-1};
    ArrayList<Integer> queue = new ArrayList<>();

    public static void main(String args[]) throws IOException {
        test obj = new test();
        obj.start();
    }

    void start() throws IOException {
        Reader sc = new Reader();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        // Scanner sc=new Scanner(System.in);
        String s1[]=br.readLine().split(" ");
        int n=Integer.parseInt(s1[0]);
        int a=Integer.parseInt(s1[1]);
        String s=br.readLine();
        int b[]=new int[26];
        for(int i=0;i<n;i++)
        {
            b[s.charAt(i)-65]+=1;
        }
        Arrays.sort(b);
        long count=0;
        int t=25;
        while(a>0)
        {
            count+=(long)Math.min(b[t],a)*(long)Math.min(b[t],a);
            a=a-Math.min(b[t],a);
            t--;
        }
        out.println(count);

    }

    //<---------------------------------------------------------------------------------------------------------------->//


    //printing 2-d array
    private void println(int[][] a,int n,int m) {
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
                System.out.print(a[i][j]);
            System.out.println();
        }

    }


    //modified dfs for chessboard, matrix
    void dfs(char a[][],int i,int j,char t,int n,int m)
    {
        //visited[i]=true;
        a[i][j]=t;
        if(t=='B')
            t='W';
        else
            t='B';
        for (int c= 0; c < 4; c++) {

            int temp=i+sign[2*c];
            int temp2=j+sign[2*c+1];
            if(temp>=0&&temp<n&&temp2>=0&&temp2<m) {
                if(a[temp][temp2]=='.'&&a[temp][temp2]!='-')
                    dfs(a,temp,temp2,t,n,m);
            }
        }
    }


     //constructing segment tree
    private void constructseg(long[] seg, long[] input, int p, int q, int pos) {
        if(p==q)
        {
            seg[pos]=input[p];
            return;
        }
        int mid=(q+p)/2;
        constructseg(seg,input,p,mid,2*pos+1);
        constructseg(seg,input,mid+1,q,2*pos+2);
        seg[pos]=seg[2*pos+1]+seg[2*pos+2];
    }


    //traversing through a arrayList graph
    void dfs(ArrayList<Integer> node[],int i,int count,int cat[],int k)
    {
        visited[i]=true;
        if(cat[i]==1) {
            count++;
        }
        else
            count=0;
        if(count>k) {
            return;
        }
        if(node[i].size()==1&&i!=0) {
            max += 1;
        }
        for (int j = 0; j < node[i].size(); j++) {
            if(!visited[node[i].get(j)])
                dfs(node, node[i].get(j), count, cat, k);
        }

    }


    //printing arraylist array
    void println(ArrayList<Integer> a[])
    {
          for (ArrayList<Integer> b:a
               ) {
              System.out.println(b.toString());
          }
    }

    //sorting 2 array based on a, Complexity is O(n^2)
    void sort(int a[],int b[],int n)
    {
        for(int i=1;i<n;i++)
        {
            int index=i;
            for(int j=i-1;j>=0;j--)
            {
              //  println(a);
                if(a[index]<a[j])
                {
                    int temp=a[index];
                    int temp2=b[index];
                    a[index]=a[j];
                    b[index]=b[j];
                    a[j]=temp;
                    b[j]=temp2;
                    index=j;

                }
                else
                    break;
            }
        }

    }
     // to create and initialize Integer array
    private int[] intArray(int a, Scanner sc) {
        int temp[]=new int[a];
        for(int i=0;i<a;i++) {
            temp[i]=sc.nextInt();
        }
        return temp;
    }

    private int[] intArray(int a, Reader sc) throws IOException {
        int temp[]=new int[a];
        for(int i=0;i<a;i++) {
            temp[i]=sc.nextInt();
        }
        return temp;
    }// / to create and initialize Long Array
    private long[] longArray(int a, Scanner sc) {
        long temp[]=new long[a];
        for(int i=0;i<a;i++) {
            temp[i]=sc.nextLong();
        }
        return temp;
    }

    // displaying Map contents key--value
    public static void printMap(Map mp) {
        Iterator it = mp.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry pair = (Map.Entry)it.next();
            System.out.println(pair.getKey() + " = " + pair.getValue());
            it.remove(); // avoids a ConcurrentModificationException
        }
    }


    // Return arrayList of minimum factor of number
    // 24= 2*2*2*3;
    private ArrayList<Integer> minFactor(int a) {
        ArrayList<Integer> obj=new ArrayList<>();
        for(int i=2;i<=a;i++)
        {
            while(a!=0&&a%i==0)
            {
                obj.add(i);
                a/=i;
            }
        }
        return obj;
    }


    // check whether the number is prime or not
    public static boolean isPrimeNumber(int i) {
        int factors = 0;
        int j = 1;

        while(j <= i)
        {
            if(i % j == 0)
            {
                factors++;
            }
            j++;
        }
        return (factors == 2);
    }

    // creating and initializing arrayList
    private void initArrayList(ArrayList<Integer>[] tempa) {
        for(int i=0;i<tempa.length;i++)
            tempa[i]=new ArrayList<>();
    }

    // return factorial contents as ArrayList
    private ArrayList<Integer> factdigit(int i)
    {
        ArrayList<Integer> temp=new ArrayList<>();
        for(int j=i;j>1;j--)
        {
            temp.add(j);
        }
        return temp;
    }

    //printing Integer array
    private  void println(int a[])
    {
        for(int i=0;i<a.length;i++)
            System.out.print(a[i]+" ");
    }
    int factorial(int n){
        if (n == 0)
            return 1;
        else
            return((n %1000000007)* (factorial(n-1)%1000000007));
    }
}





class Reader {
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException {
        din = new DataInputStream(new FileInputStream(file_name));
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException {
        byte[] buf = new byte[300]; // line length
        int cnt = 0, c;
        while ((c = read()) != -1) {
            if (c == '\n')
                break;
            buf[cnt++] = (byte) c;
        }
        return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException {
        int ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        } while ((c = read()) >= '0' && c <= '9');

        if (neg)
            return -ret;
        return ret;
    }

    public long nextLong() throws IOException {
        long ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');
        if (neg)
            return -ret;
        return ret;
    }

    public double nextDouble() throws IOException {
        double ret = 0, div = 1;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();

        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');

        if (c == '.') {
            while ((c = read()) >= '0' && c <= '9') {
                ret += (c - '0') / (div *= 10);
            }
        }

        if (neg)
            return -ret;
        return ret;
    }

    private void fillBuffer() throws IOException {
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
        if (bytesRead == -1)
            buffer[0] = -1;
    }

    private byte read() throws IOException {
        if (bufferPointer == bytesRead)
            fillBuffer();
        return buffer[bufferPointer++];
    }

    public void close() throws IOException {
        if (din == null)
            return;
        din.close();
    }
}
