/* package whatever; // don't place package name! */

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

/* Name of the class has to be "Main" only if the class is public. */
class Main
{
    public static void main (String[] args) throws java.lang.Exception
    {
        // your code goes here
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] lines = br.readLine().split(" ");
        int N = Integer.parseInt(lines[0]);
        long K = Long.parseLong(lines[1]);
        
        long cnt = 0;
        lines = br.readLine().split(" ");
        for(int i=1;i<=N;i++){
            if(i > Integer.parseInt(lines[i-1])){
                cnt++;
            }
        }
        
        System.out.println(K>=cnt&&(K-cnt)%2==0?"YES":"NO");
    }
}