import java.util.*;

public class Cocktail {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int potions = sc.nextInt(); //num of potions

int t = sc.nextInt(); //time to drink each potion

int[] potionTimes = new int[potions];

for(int i=0; i<potions; i++){

potionTimes[i] = sc.nextInt();//each time duration of the potions

}

Arrays.sort(potionTimes);

int minimumTime = (potions-1)*t; //minimum time it requires for all potions to be in efect

boolean isCorrect = true; //if it passes or not

for(int i=potions-1; i>0; i--){

if(potionTimes[i] <= minimumTime){

isCorrect = false;

break;

}

else{

minimumTime -= t;

}

}

if(isCorrect)

System.out.println("YES");

else

System.out.println("NO");

}

}