import java.io.*;
import java.util.*;

//solution classes here

public class Main {

    //main solution here

    static Scanner sc = new Scanner(System.in);
    static PrintWriter out = new PrintWriter(System.out);

    public static void main(String[] args) throws IOException {
        int n = sc.nextInt();
        int k = sc.nextInt();
        long a[] = new long[n];
        for(int i=0;i<n;i++) {
            a[i]=sc.nextLong();
        }
        Arrays.sort(a);
        int count=0;
        for(int i=0;i<n;) {
            if(i+k-1>=n-1) {
                if(a[i]!=a[n-1]) {
                    count++;
                    i=n;
                }
            }
            else if(a[i]!=a[i+k-1]) {
                count++;
                i=i+k-1;
            }
        }

        out.println(count);




        out.flush();
        out.close();
    }

    //solution functions here

    /*
     * ******************************************************************************************************************************
     * ******************************************************************************************************************************
     * ******************************************************************************************************************************
     * #########  #######  ######   ########  ##  ###   ##  ##    ##   #######  ##    ##   #######  ##   ##  #######   ########
     * ##    ###  ##       ##       ########  ##  ## #  ##   ##  ##    ##       ##    ##   ##       ##  ##   ##        ##    ##
     * ##    ###  #######  ######      ##     ##  ##  # ##     ##      #######  ##    ##   ##       ####     #######   ########
     * ##    ###  ##           ##      ##     ##  ##   ###     ##      ##       ##    ##   ##       ##  ##   ##        ##   ##
     * #########  #######  ######      ##     ##  ##    ##     ##      ##       ########   #######  ##   ##  #######   ##     ##
     *******************************************************************************************************************************
     *******************************************************************************************************************************
     *******************************************************************************************************************************
     */

    static class Scanner {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s) {
            br = new BufferedReader(new InputStreamReader(s));
        }

        public Scanner(FileReader fileReader) {
            br = new BufferedReader(fileReader);
        }

        public String next() throws IOException {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

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

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

        public String nextLine() throws IOException {
            return br.readLine();
        }

        public boolean ready() throws IOException {
            return br.ready();
        }
    }
}

/* *****************************************************************************************************************************
 * I'M NOT IN DANGER, I'M THE DANGER!!!
 * *****************************************************************************************************************************
 */

Measured memory_bytes: 35440