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 java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Random;
import java.util.StringTokenizer;

public class A {

	public static void main(String[] args) throws IOException {

		FastScanner sc = new FastScanner();
		PrintWriter out = new PrintWriter(System.out);
		int n = sc.nextInt();
		long k = sc.nextLong();
		HashMap<Character, Integer> map = new HashMap<Character, Integer>();
		String str = sc.next();
		for(char e : str.toCharArray()) {
			map.put(e, map.getOrDefault(e, 0)+1);
		}
		ArrayList<Integer> lis  =new ArrayList<Integer>();
		for(int v : map.values())lis.add(v);
		Collections.sort(lis,Collections.reverseOrder());
		long ans = 0;
		for(int val : lis) {
			if(val<=k) {
				ans = ans + val*(long)val;
				k-=val;
			}
			else {
				ans = ans + k*k;
				break;
			}
		}
		System.out.println(ans);
		

	}

	static void ruffleSort(int[] a) {
		Random get = new Random();
		for (int i = 0; i < a.length; i++) {
			int r = get.nextInt(a.length);
			int temp = a[i];
			a[i] = a[r];
			a[r] = temp;
		}
		Arrays.sort(a);
	}

	static void ruffleSort(long[] a) {
		Random get = new Random();
		for (int i = 0; i < a.length; i++) {
			int r = get.nextInt(a.length);
			long temp = a[i];
			a[i] = a[r];
			a[r] = temp;
		}
		Arrays.sort(a);
	}

	static class Pair implements Comparable<Pair> {
		int x, y;

		Pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

		@Override
		public int compareTo(Pair o) {
			return Integer.compare(this.x, o.x);
		}

	}

	static class FastScanner {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer("");

		String next() {
			while (!st.hasMoreTokens())
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}

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

		int[] readArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		long[] readArrayLong(int n) {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

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

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	static int ceil(int x, int y) {
		return (x % y == 0 ? x / y : (x / y + 1));
	}

	static long ceil(long x, long y) {
		return (x % y == 0 ? x / y : (x / y + 1));
	}

	static int max(int x, int y) {
		return Math.max(x, y);
	}

	static int min(int x, int y) {
		return Math.min(x, y);
	}

	static long max(long x, long y) {
		return Math.max(x, y);
	}

	static long min(long x, long y) {
		return Math.min(x, y);
	}

	static int min(int a[]) {
		int x = 1_000_000_00_9;
		for (int i = 0; i < a.length; i++)
			x = min(x, a[i]);
		return x;
	}

	static int max(int a[]) {
		int x = -1_000_000_00_9;
		for (int i = 0; i < a.length; i++)
			x = max(x, a[i]);
		return x;
	}

	static long min(long a[]) {
		long x = (long) 3e18;
		for (int i = 0; i < a.length; i++)
			x = min(x, a[i]);
		return x;
	}

	static long max(long a[]) {
		long x = -(long) 3e18;
		for (int i = 0; i < a.length; i++)
			x = max(x, a[i]);
		return x;
	}

	static int power(int x, int y) {
		int res = 1;
		while (y > 0) {
			if (y % 2 == 1)
				res = (res * x);
			y >>= 1;
			x = (x * x);
		}
		return res;
	}

	static long power(long x, long y) {
		long res = 1;
		while (y > 0) {
			if (y % 2 == 1)
				res = (res * x);
			y >>= 1;
			x = (x * x);
		}
		return res;
	}

	static void intsort(int[] a) {
		List<Integer> temp = new ArrayList<Integer>();
		for (int i = 0; i < a.length; i++)
			temp.add(a[i]);
		Collections.sort(temp);
		for (int i = 0; i < a.length; i++)
			a[i] = temp.get(i);
	}

	static void longsort(long[] a) {
		List<Long> temp = new ArrayList<Long>();
		for (int i = 0; i < a.length; i++)
			temp.add(a[i]);
		Collections.sort(temp);
		for (int i = 0; i < a.length; i++)
			a[i] = temp.get(i);
	}

	static void reverseintsort(int[] a) {
		List<Integer> temp = new ArrayList<Integer>();
		for (int i = 0; i < a.length; i++)
			temp.add(a[i]);
		Collections.sort(temp);
		Collections.reverseOrder();
		for (int i = 0; i < a.length; i++)
			a[i] = temp.get(i);
	}

	static void reverselongsort(long[] a) {
		List<Long> temp = new ArrayList<Long>();
		for (int i = 0; i < a.length; i++)
			temp.add(a[i]);
		Collections.sort(temp);
		Collections.reverseOrder();
		for (int i = 0; i < a.length; i++)
			a[i] = temp.get(i);
	}

	static class longpair implements Comparable<longpair> {
		long x, y;

		longpair(long x, long y) {
			this.x = x;
			this.y = y;
		}

		public int compareTo(longpair p) {
			return Long.compare(this.x, p.x);
		}
	}

	public static int gcd(int a, int b) {
		BigInteger b1 = BigInteger.valueOf(a);
		BigInteger b2 = BigInteger.valueOf(b);
		BigInteger gcd = b1.gcd(b2);
		return gcd.intValue();
	}

	public static long gcd(long a, long b) {
		BigInteger b1 = BigInteger.valueOf(a);
		BigInteger b2 = BigInteger.valueOf(b);
		BigInteger gcd = b1.gcd(b2);
		return gcd.longValue();
	}
}
