#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;


int main() {
	int m, n;

	cin >> m >> n;
	vector<int> c(n);
	for (int i = 0; i < n; i++) {
		cin >> c[i];
	}

	vector<int> dp(m + 1, 0);
	for (int i = m; i > 0; i--) {
		if (i == m || dp[i] > 0) {
			for (int j = 0; j < n; j++) {
				int to = i - c[j];
				if (to >= 0) {
					dp[to] = max(dp[to], dp[i] + 1);
				}
			}
		}
	}

	vector<bool> isPrime(m + 1, true);
	isPrime[0] = isPrime[1] = false;
	for (int i = 2; i * i <= m; i++) {
		if (!isPrime[i]) {
			continue;
		}
		for (int j = 2 * i; j < m; j += i) {
			isPrime[j] = false;
		}
	}

	int ans = 0;
	for (int i = 1; i <= m; i++) {
		if (isPrime[i]) {
			ans += dp[i];
		}
	}
	ans += *max_element(dp.begin(), dp.end());

	cout << ans << endl;
	return 0;
}