#include <limits>
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = uint32_t;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

vector<int> get_prime(int n) {
    if(n <= 1) return vector<int>{};
    vector<bool> is_composite(n);
    vector<int> prime;
    for (int i = 2; i <= n; ++i) {
        if(!is_composite[i]) prime.push_back(i);
        for (auto &&j : prime) {
            if(i*j > n) continue;
            is_composite[i*j] = true;
            if(i % j == 0) break;
        }
    }
    return prime;
}

int main() {
    int m, n;
    cin >> m >> n;
    vector<int> v(n);
    for (auto &&k : v) scanf("%d", &k);
    vector<int> dp(m+1, -INF<int>);
    dp[m] = 0;
    for (int i = 0; i < n; ++i) {
        for (int j = m; j >= v[i]; --j) {
            dp[j-v[i]] = max(dp[j-v[i]], dp[j]+1);
        }
    }
    auto p = get_prime(m);
    ll ans = 0;
    for (auto &&l : p) {
        ans += max(0, dp[l]);
    }
    ans += *max_element(dp.begin(),dp.end());
    cout << ans << "\n";
    return 0;
}