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

using namespace std;

int dp[10001];
bool prime[10001];

int main(){
	int m, n;
	cin >> m >> n;
	vector<int> c(n);
	for(int &i : c){
		cin >> i;
	}
	for(int i = 2; i <= 10000; i++){
		prime[i] = true;
	}
	vector<int> p;
	for(int i = 2; i <= m; i++){
		if(prime[i]){
			p.push_back(i);
			for(int j = i * 2; j <= m; j += i){
				if(prime[j]) prime[j] = false;
			}
		}
	}
	dp[m] = 1;
	for(int i : c){
		for(int j = m; j >= i; j--){
			if(dp[j] > 0){
				dp[j - i] = max(dp[j] + 1, dp[j - i]);
			}
		}
	}
	int ans = *max_element(dp, dp + m) - 1;
	for(int i : p){
		ans += max(0, dp[i] - 1);
	}
	cout << ans << endl;
	return 0;
}