wa#1#4

#include<bits/stdc++.h>

using namespace std;

bool isprime(int n)
{
    bool ret=true;
    for(int i=2;i<n;i++)
    {
        if(n%i==0)
        {
            ret=false;
        }
    }
    return ret;
}

int repeat(int n)
{
    double total=1;
    for(int i=2;i<=n;i++)
    {
        total*=i;
    }
    return total;
}

int main(){
    int n,k;
    cin>>n>>k;
    int arr[n];
    int counter=0,sum=0;
    for (int i=0;i<n;i++)
    {
        cin>>arr[i];
    }
    sort(arr,arr+n);

    do{
        sum=0;
		for (int i=0;i<k;i++)
        {
            sum+=arr[i];
        }
        if(isprime(sum))
        {
            counter++;
        }


	}while(next_permutation(arr,arr+n));
    cout<<counter/repeat(n-k)/repeat(k);

    return 0;
}