#include <iostream>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <iomanip>
using namespace std;
typedef long long ll;
const int INF = 1000000;
int dp[20000];

vector<int> sieve_of_eratosthenes(int n) {
	vector<int> primes(n);
	for(int i = 2; i < n; ++i)
		primes[i] = i;
	for(int i = 2; i*i < n; ++i)
		if(primes[i])
			for(int j = i*i; j < n; j += i)
				primes[j] = 0;
	return primes;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int M, N;
	cin >> M >> N;
	fill(dp, dp + M + 1000, -INF);
	dp[0] = 0;

	int C[20];
	for(int i = 0; i < N; i++) {
		cin >> C[i];
		for(int j = 0; j + C[i] <= M; j++) {
			if(dp[j] != -INF)
				dp[j + C[i]] = max(dp[j + C[i]], dp[j] + 1);
		}
	}

	vector<int> ps = sieve_of_eratosthenes(M + 100);

	ll ans = 0;
	for(int i = 1; i < M; i++) {
		int rem = M - i;
		if(ps[rem] && dp[i] != -INF) {
			ans += dp[i];
		}
	}
	ans += *max_element(dp, dp + M + 1);
	cout << ans << endl;
}