/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.06.02 21:46:20
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;

int main() {
    int m;
    cin >> m;
    int n;
    cin >> n;
    // エラトステネスの篩 O(NloglogN)
    // N以下の素数
    int N = m;
    vector< bool > isprime(N + 1, true);
    vector< int > prime;
    isprime[0] = isprime[1] = false;
    for (int i = 2; i * i <= N; i++) {
        if (isprime[i]) {
            for (int j = i + i; j <= N; j += i) {
                isprime[j] = false;
            }
        }
    }
    for (int i = 2; i <= N; i++) {
        if (isprime[i]) {
            prime.push_back(i);
        }
    }
    constexpr int INF = 1e9 + 6;
    vector< int > dp(m + 1, -INF);
    dp[0] = 0;
    ll ans = 0;
    for (int i = 0; i < n; i++) {
        int c;
        cin >> c;
        for (int j = c; j <= m; j++) {
            if (dp[j - c] == -INF) continue;
            dp[j] = max(dp[j], dp[j - c] + 1);
            ans = max(ans, (ll)dp[j]);
        }
    }
    for (int i = 0; i < prime.size(); i++) {
        if (dp[m-prime[i]] == -INF) continue;
        ans += dp[m-prime[i]];
    }
    cout << ans << endl;
    return 0;
}