#include <bits/stdc++.h>//k-1 N-k
using namespace std;
int a[10000]; 
int main(){
	int N,m,i,k,l,j;
	cin>>N;
	cin>>k;
	bool t=1;
	for(i=0;i<N;i++)
	{
		cin>>a[i];
	}
	for(i=0;i<N-1;i++)
	{
		for(j=i+1;j<=N-1;j++)
		if(a[i]>a[j]) swap(a[i],a[j]);
	}
	m=a[N-k]-a[k-1];
	if(m==1||m==0) t=0;
	else for(i=2;i*i<=N;i++)
		{
			if(m%i==0)
			{
				t=1;break;
			}
		}
	if(t==1)cout<<"YES"<<endl<<m;
	else cout<<"N0"<<endl<<m;
	return 0;
	}
/**************************************************************
	Problem: 1242
	User: ljl2
	Language: C++
	Result: Wrong Answer
****************************************************************/