#include "bits/stdc++.h"
#define _CRT_SECURE_NO_WARNINGS
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout << (p) << endl;
#define sP(p) cout << setprecision(15) << fixed << p << endl;
#define Pi pair<int,int>
#define IINF 1e9
#define LINF 1e18
#define vi vector<int>
#define mp make_pair
#define pb push_back

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 0, 1,0,-1};
int dy[] = { 1, 0,-1,0};
int dx8[] = { -1,-1,-1,0,0,1,1,1};
int dy8[] = { -1,0,1,-1,1,-1,0,1};

unsigned long long sttoi(std::string str) {
	unsigned long long ret;
	std::stringstream ss; ss << str;
	ss >> ret;
	return ret;
}

ull gcd(ull a, ull b) {
	if (b > a)swap(a, b);
	if (b == 0) return a;
	return gcd(b, a%b);
}

int comb(int n, int k) {
	int ans = 1;
	for (int i = 0; i < min(k, n - k); i++) {
		ans *= n - i;
		ans /= i + 1;
	}
	return ans;
}

ll mod_pow(ll n,ll p,ll mod){	
	if (p == 0) return 1 % mod;
	if (p < 2) {
		return n % mod;
	}else {
		ll d = 2, value = (n%mod)*(n%mod)%mod;
		while (d*2 < p) { d *= 2;	value *= value;	value %= mod;}
		value %= mod;
		return ((value%mod) * (mod_pow(n, p - d, mod)%mod)) % mod;
	}
}

bool isPrime(int n) {
	if (n <= 1)return false;
	if (n == 2)return true;
	if (n % 2 == 0)return false;
	for (int i = 3; i*i <= n; i += 2) {
		if (n%i == 0)return false;
	}
	return true;
}

void solve() {
	int m, n;
	vi c;
	cin >> m >> n;
	rep(i, n) {
		int a;
		cin >> a;
		c.push_back(a);
	}
	int dp[10010];
	rep(i, 10010) {
		dp[i] = 0;
	}
	rep(i, n) {
		dp[m - c[i]] = 1;
	}
	for (int i = 0; i < n; i++) {
		for (int j = m; j >= 0; j--) {
			if (j - c[i] >= 0 && dp[j] != 0) {
				dp[j - c[i]] = max(dp[j] + 1, dp[j - c[i]]);
			}
		}
	}
	int ans = 0;
	REP(i, 2, m + 1) {
		if (dp[i] != 0 && isPrime(i)) {
			ans += dp[i];
		}
	}
	int maxi = -1;
	rep(i, m + 1) {
		if (dp[i] > maxi) {
			maxi = dp[i];
		}
	}
	ans += maxi;
	P(ans);
}

int main() {
	solve();
	return 0;
}