#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
#define RALL(A) A.rbegin(),A.rend()
typedef long long LL;
typedef pair<int,int> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
const LL mod=1000000007;
const LL LINF=1LL<<62;
const int INF=1<<30;
int dx[]={1,0,-1,0,1,-1,1,-1};
int dy[]={0,1,0,-1,1,-1,-1,1};



vector<int> Sieve(int n){
    vector<int> ret(n + 1, 0);
    vector<int> pr;
    for (int i = 2; i <= n; i++) {
        if (ret[i] == 0) {
            ret[i] = i;
            pr.emplace_back(i);
        }
        for (int j = 0; j < pr.size() && pr[j] <= ret[i] && i*pr[j] <= n; j++) ret[i * pr[j]] = pr[j];
    }
    ret[0] = -1;
    return ret;
}

int main(){
    int m,n;cin >> m >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    vector<int> dp(m+1,-INF);
    dp[m] = 0;
    for (int i = 0; i < n; i++) {
        for (int j = m; j >= 0; j--) {
            if(j - a[i] >= 0) chmax(dp[j - a[i]], dp[j] + 1);
        }
    }
    auto p = Sieve(m);
    int ans = 0, mx = 0;
    for (int i = 0; i <= m; i++) {
        if(p[i] == i){
            if(dp[i] > 0) ans += dp[i];
        }
        else chmax(mx, dp[i]);
    }
    cout << ans + mx << endl;
    return 0;
}