/*
ID: fanzeyi1
LANG: C
TASK: orz 
*/
/*
 * =====================================================================================
 *
 *       Filename:  orz.c
 *        Version:  1.0
 *        Created:  11/08/2011 10:31:29 AM
 *       Revision:  none
 *       Compiler:  gcc
 *         Author:  Zeray Fan, fanzeyi1994[at]gmail.com
 *        Company:  http://www.fanhe.org/
 *
 * =====================================================================================
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int num[2502]; 
int f[2502]; 

inline int min(int a, int b){
    return a < b ? a : b; 
}

int main(void) {
    FILE *fin = fopen("orz.in","r");
    FILE *fout = fopen("orz.out", "w");
    int i, j; 
    int n, m;
    int cow1, cow2; 
    memset(num, 0, sizeof(num)); 
    memset(f, 0x7F, sizeof(f)); 
    f[0] = 0; 
    fscanf(fin, "%d %d", &n, &m); 
    for( i = 1 ; i <= n ; i++ ) {
        fscanf(fin, "%d", &num[i]); 
    }
    for( i = 1 ; i <= n ; i++ ) {
        cow1 = 0; 
        cow2 = 0; 
        if(num[i]&1) {
            cow1 = 1; 
        }else{
            cow2 = 1; 
        }
        for( j = i - 1 ; j >= 0 ; j-- ) {
            if(!(abs(cow1 - cow2) > m && !(cow1 == 0 || cow2 == 0))) {
                f[i] = min(f[i], f[j]+1);
            }
            if(num[j]&1) {
                cow1 = cow1 + 1; 
            }else{
                cow2 = cow2 + 1; 
            }
        }
    }
    fprintf(fout, "%d\n", f[n]); 
    return 0;
}