#include <stdio.h>
#define N (10000+5)
int find_kMax(int[], int, int);
int find_kMin(int[], int, int);
int is_prime(int);

int main()
{
	int i,n,k;
	int a[N];
	scanf("%d%d", &n, &k);
	for ( i = 0; i < n; i++)
	{
		scanf("%d", &a[i]);
	}
	int max = find_kMax(a, n, k);
	int min = find_kMin(a, n, k);
	if (is_prime(max - min))
		printf("YES\n");
	else
		printf("NO\n");
	printf("%d\n", max - min);
	return 0;
}
int find_kMax(int a[], int n, int k)
{
	int min;
	int x;
	for (int i = 0; i<n - 1; i++)
	{
		min = i;
		for (int j = i; j<n; j++)
		{
			if (a[j]<a[min])
			{
				min = j;
			}
		}
		x = a[i]; a[i] = a[min]; a[min] = x;
	}
	return a[n - k];
}
int find_kMin(int a[], int n, int k)
{
	int min;
	int x;
	for (int i = 0; i<n - 1; i++)
	{
		min = i;
		for (int j = i; j<n; j++)
		{
			if (a[j]<a[min])
			{
				min = j;
			}
		}
		x = a[i]; a[i] = a[min]; a[min] = x;
	}
	return a[k - 1];
}
int is_prime(int x)
{
	if (x<2) return 0;
	else
	{
		int flag = 1;
		for (int i = 2; i<x / 2; i++)
		{
			if (x%i == 0) { flag = 0; break; }
		}
		return flag;
	}
}