#include <bits/stdc++.h>
using namespace std;

template<class T1, class T2> bool chmin(T1 &a, T2 b) { if (b < a) { a = b; return true; } return false; }
template<class T1, class T2> bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return true; } return false; }

int main() {
	vector<bool> is_prime(10101, true);
	is_prime[0] = is_prime[1] = false;
	for (int i = 2; i < 10101; i++) {
		if (is_prime[i]) {
			for (int j = i * 2; j < 10101; j += i) {
				is_prime[j] = false;
			}
		}
	}

	int m, n;
	cin >> m >> n;

	vector<int> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];

	static int dp[22][10101];
	fill_n(*dp, 22 * 10101, -1e9);
	dp[0][0] = 0;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j <= m; j++) {
			chmax(dp[i + 1][j], dp[i][j]);
			if (j - a[i] >= 0) chmax(dp[i + 1][j], dp[i + 1][j - a[i]] + 1);
		}
	}

	int mx = 0; 
	for (int i = 0; i <= m; i++) {
		mx = max(mx, dp[n][i]);
	}

	long long sum = mx;
	for (int i = 0; i <= m; i++) {
		if (is_prime[m - i]) {
			if (dp[n][i] >= 0) sum += dp[n][i];
		}
	}
	cout << sum << endl;
}