#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repp(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
using namespace std;

int prime[10010];
bool is_prime[10010];

void sieve(int n){
    int p = 0;
    rep(i, 0, n + 1) is_prime[i] = true;
    is_prime[0] = is_prime[1] = false;
    rep(i, 2, n + 1){
        if(is_prime[i]) prime[p++] = i;
        for(int j = 2*i; j <= n; j += i) is_prime[j] = false;
    }
    return;
}

int dp[10010];

signed main(){
    int m, n;
    cin >> m >> n;
    sieve(m);
    vector<int> c(n);
    rep(i, 0, n) cin >> c[i];
    // dp[m] = 1;
    rep(i, 0, n){
        repb(j, m, 0){
            if(j + c[i] <= m && (dp[j + c[i]] != 0 || j + c[i] == m)){
                dp[j] = max(dp[j], dp[j + c[i]] + 1);
            }
        }
    }
    int ans = 0, MAX = 0;
    rep(i, 0, m){
        // cout << i << ' ' << dp[i] << endl;
        if(is_prime[i]){
            // cout << i << "        " << dp[i] << endl;
            ans += dp[i];
        }
        MAX = max(MAX, dp[i]);
    }
    cout << ans + MAX << endl;
}