#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e8;
using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
#else
	#define DEBUG(x) true
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef pair<int,int> P;
typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<LL,LL> LP;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

std::vector<bool> eratosthenes(int n){
	std::vector<bool> res(n+1,true);
	res[0] = false;
	res[1] = false;
	for(int i = 2; i*i <= n; i++){
		for(int j = 2; i*j <= n; j++){
			res[i*j] = false;
		}
	}
	return res;
}

int main()
{
	ios_init();
	int m,n;
	cin >> m >> n;
	vector<int> c(n);
	REP(i,n) cin >> c[i];
	auto sosu = eratosthenes(m+1);
	vector<int> dp(m+1,-INF);
	dp[m] = 0;
	REP(i,n){
		RREP(j,m+1-c[i]){
			dp[j] = max(dp[j+c[i]]+1,dp[j]);
		}
	}
	int ans = 0;
	REP(i,m){
		if(sosu[i] and dp[i] >= 0) ans += dp[i];
	}
	/*REP(i,SZ(dp)) if(dp[i] >= 0){
		DEBUG(i); DEBUG(dp[i]);
	}*/
	ans += *max_element(ALL(dp));
	cout << ans << endl;
	return 0;
}