深搜

#include <iostream>
#include <cstdio>
using namespace std;
int a[25], n, m;
bool check(int n){
	if(n < 2) return 0;
	if(n == 2) return 1;
	if(n % 2 == 0) return 0;
	for(int i = 3; i * i <= n; i += 2){
		if(n % i == 0) return 0;
	}
	return 1;
}
int dfs(int ct, int idx, int val){
	if(ct == m) return check(val);
	int cnt = 0;
	for(int i = idx + 1; i <= n; i++){
		cnt += dfs(ct + 1, i, val + a[i]);
	}return cnt;
}
int main(){
	cin >> n >> m;
	for(int i = 1; i <= n; i++){
		cin >> a[i];
	}cout << dfs(0, 0, 0);

	return 0;
}