Emily's birthday is next week and Jack has decided to buy a present for her. He knows she loves books so he goes to the local bookshop, where there are n books on sale from one of m genres.

In the bookshop, Jack decides to buy two books of different genres.

Based on the genre of books on sale in the shop, find the number of options available to Jack for choosing two books of different genres for Emily. Options are considered different if they differ in at least one book.

The books are given by indices of their genres. The genres are numbered from 1 to m.

Input

The first line contains two positive integers n and m (2 ≤ n ≤ 2·105, 2 ≤ m ≤ 10) — the number of books in the bookstore and the number of genres.

The second line contains a sequence a1, a2, ..., an, where ai (1 ≤ ai ≤ m) equals the genre of the i-th book.

It is guaranteed that for each genre there is at least one book of that genre.

Output

Print the only integer — the number of ways in which Jack can choose books.

It is guaranteed that the answer doesn't exceed the value 2·109.

Examples

Input

4 3
2 1 3 1


Output

5


Input

7 4
4 2 3 1 2 4 3


Output

18

Note

The answer to the first test sample equals 5 as Sasha can choose:

  1. the first and second books, 
  2. the first and third books, 
  3. the first and fourth books, 
  4. the second and third books, 
  5. the third and fourth books. 
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Scanner;
import java.util.TreeMap;

import javafx.util.Pair;

public class Main {

    public static void solve() {
        int n = IO.readInt();
        int m = IO.readInt();
        int[] counts = new int[m];
        for (int index = 0; index < n; ++index) {
            counts[IO.readInt() - 1]++;
        }
        int answer = 0;
        for (int index = 0; index < m; ++index){
            n -= counts[index];
            answer += n * counts[index];
        }
        IO.println(answer);
    }

    // Input/Output ================================
    public static class IO {

        private static Scanner scanner;
        private static PrintWriter writer;

        public static void setUp(InputStream in, OutputStream out) {
            scanner = new Scanner(new java.io.BufferedInputStream(in));
            writer = new PrintWriter(out);
        }

        public static boolean isEmpty() {
            return !scanner.hasNext();
        }

        public static boolean hasNextLine() {
            return scanner.hasNextLine();
        }

        public static String readLine() {
            String line;
            try {
                line = scanner.nextLine();
            }
            catch (Exception e) {
                line = null;
            }
            return line;
        }

        public static String readString() {
            return scanner.next();
        }

        public static int readInt() {
            return scanner.nextInt();
        }

        public static int[] readIntArray(int n) {
            int[] a = new int[n];
            for (int index = 0; index < n; ++index) {
                a[index] = readInt();
            }
            return a;
        }

        public static Pair<Integer, Integer>[] readIntArrayWithIndexes(int n) {
            Pair<Integer, Integer>[] a = new Pair[n];
            for (int index = 0; index < n; ++index) {
                a[index] = new Pair<>(index, readInt());
            }
            return a;
        }

        public static double readDouble() {
            return scanner.nextDouble();
        }

        public static float readFloat() {
            return scanner.nextFloat();
        }

        public static long readLong() {
            return scanner.nextLong();
        }

        public static char readChar() {
            return scanner.findInLine("[^\\s]").charAt(0);
        }

        public static void print(Object o) {
            writer.print(o);
            writer.flush();
        }

        public static void println(Object o) {
            writer.println(o);
            writer.flush();
        }
    }

    // Algorithms ================================

    private static class Algo {

        private static int binSearch(int[] array, int n, int lo, int hi) {
            if (lo > hi) {
                return lo;
            }

            int mid = lo + (hi - lo) / 2;
            int cmp = (int) java.lang.Math.signum(n - array[mid]);
            if (cmp < 0) {
                return binSearch(array, n, lo, mid - 1);
            }
            else if (cmp == 0) {
                return mid;
            }
            else {
                return binSearch(array, n, mid + 1, hi);
            }
        }

        private static void permutations(int n) {
            int[] p = new int[n];
            for (int index = 0; index < n; ++index) {
                p[index] = index + 1;
            }

            while (true) {
                IO.println(Arrays.toString(p));

                int k = n - 1;
                while (k > 0) {
                    if (p[k] < p[k - 1]) {
                        k--;
                    }
                    else {
                        break;
                    }
                }
                if (k == 0) {
                    break;
                }
                int j = n - 1;
                while (p[j] < p[k - 1]) {
                    j--;
                }

                int t = p[j];
                p[j] = p[k - 1];
                p[k - 1] = t;

                int i = 0;
                while (k + i < n - 1 - i) {
                    t = p[k + i];
                    p[k + i] = p[n - i - 1];
                    p[n - i - 1] = t;
                    i++;
                }
            }
        }

        private static boolean isPrime(int number) {
            if (number <= 1) {
                return false;
            }
            if (number <= 3) {
                return true;
            }
            if (number % 2 == 0 || number % 3 == 0) {
                return false;
            }
            int i = 5;
            while (i * i <= number) {
                if (number % i == 0 || number % (i + 2) == 0) {
                    return false;
                }
                i += 6;
            }
            return true;
        }

        private static boolean isPrimeOrOne(int number) {
            return number == 1 || isPrime(number);
        }

        private static boolean isPalindrome(int number) {
            int n = number;
            int reverse = 0;
            while (n > 0) {
                reverse *= 10;
                reverse += (n % 10);
                n /= 10;
            }
            return reverse == number;
        }

        public static int gcd(int a, int b) {
            while (b != 0) {
                int tmp = a % b;
                a = b;
                b = tmp;
            }
            return a;
        }
    }

    private static class Math2 {

        static long c(int n, int k) {
            if (n == 0 && k == 0) {
                return 1;
            }
            int d = 1000;
            int l = 1000000007;
            long[][] c = new long[d + 1][d + 1];
            for (int i = 1; i <= d; ++i) {
                for (int j = 0; j <= i; ++j) {
                    if (i == j || j == 0) {
                        c[i][j] = 1;
                    }
                    else {
                        c[i][j] = (c[i - 1][j - 1] + c[i - 1][j]) % l;
                    }
                }
            }
            return c[n][k];
        }
    }

    static class Pair<K, V> {
        K key;
        V value;

        Pair(K key, V value) {
            this.key = key;
            this.value = value;
        }
    }

    public static void main(String[] args) {
        IO.setUp(System.in, System.out);
        /*
        try {
            IO.setUp(new FileInputStream("encode.in"), new FileOutputStream("encode.out"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return;
        }
        */
        solve();
    }
}
