#include <bits/stdc++.h>

using namespace std;

int dp1[21][10001] = {}, dp2[21][10001] = {};
bool is_prime[10001];
vector<int> prime;

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

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int m, n;
    cin >> m >> n;
    vector<int> c(n);
    for (int i = 0; i < n; i++) cin >> c[i];
    sieve(m);
    bool check[10001] = {};
    check[m] = true;
    for (int i = 1; i <= n; i++) {
        for (int j = m; j > m - c[i - 1]; j--) dp1[i][j] = dp1[i - 1][j];
        for (int j = m - c[i - 1]; j >= 2; j--) {
            if (check[j + c[i - 1]]) {
                dp1[i][j] = max(dp1[i - 1][j], dp1[i][j + c[i - 1]] + 1);
                check[j] = true;
            } else {
                dp1[i][j] = dp1[i - 1][j];
            }
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < c[i - 1]; j++) dp2[i][j] = dp2[i - 1][j];
        for (int j = c[i - 1]; j <= m; j++) {
            dp2[i][j] = max(dp2[i - 1][j], dp2[i][j - c[i - 1]] + 1);
        }
    }
    int ans = dp2[n][m];
    for (int i = 0; i < (int)prime.size(); i++) {
        if (check[prime[i]]) ans += dp1[n][prime[i]];
    }
    cout << ans << "\n";
    return 0;
}