using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		long t = 0;
		for(int i=0;i<N;i++){
			if(D[i] > i+1) t++;
		}
		
		//Console.WriteLine(t);
		
		if(t > K){
			Console.WriteLine("NO");
			return;
		}
		
		Console.WriteLine( (t-K)%2 == 0 ? "YES" : "NO");
		
	}
	int N;
	long K;
	int[] D;
	public Sol(){
		var d = rla();
		N = (int) d[0];
		K = d[1];
		D = ria();
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}
class BIT{
	int MM;
	int n;
	long[] bit;
	public BIT(int n_){
		n=n_;
		MM=1<<18;
		while(MM<n*2)MM<<=1;
		bit=new long[MM+1];
	}
	//1-origin!!
	public void Add(int i,int x){
		while(i<=n){
			bit[i]+=x;
			i+=(i&-i);
		}
	}
	
	// i=>sum(a_1,...,a_i)
	// i=0 -> return 0;
	public long Sum(int i){
		long s=0;
		while(i>0){
			s+=bit[i];
			i-= (i&-i);
		}
		return s;
	}
}