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

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(); // bulbs;
        int k = sc.nextInt(); // no. of bulbs turned off
        int result = 0;
        long a[] = new long[n];
        for(int i = 0; i<n; i++) {
            a[i] = sc.nextLong();
        }
        for(int j = 0; j<n; j++) {
            long min = a[0];
            int min_pos = 0;
            for(int x = 1; x<n; x++) {
                if(a[x] < min)  {
                    min = a[x];
                    min_pos = x;
                }
            }
            if(min == 1000000001)   break;
            int start = min_pos - k;
            if(start < 0)   start = 0;
            int end = min_pos + k;
            if(end > n-1)   end = n-1;
            for(int y = start; y<=end; y++) {
                if(a[y] < 1000000001)  {
                    a[y] = 1000000001;
                }
            }
            
            result++;
        }
        System.out.println(result);
    }
}