#include <cstdio>
#include <iostream>
#include <algorithm>

using namespace std;

#define rep(i,x) for(int i=0;i<(x);++i)
#define rep1(i,x) for(int i=1;i<=(x);++i)

const int inf = 1e9;

bool is_prime[10001];
bool used[10001];
bool can_make[10001];
int memo[10001];

int M, N, C[21];

void sieve()
{
    fill(is_prime, is_prime + 10001, true);

    is_prime[0] = is_prime[1] = false;

    for (int i = 2; i <= 10000; ++i) {
        if (!is_prime[i]) continue;
        is_prime[i] = true;

        for (int j = i * 2; j <= 10000; j += i) {
            is_prime[j] = false;
        }
    }
}

int calc(int a)
{
    int& res = memo[a];

    if (a == 0) return 0;
    if (~res) return res;

    res = -inf;

    rep(i, N) {
        if (a - C[i] < 0) break;
        res = max(res, 1 + calc(a - C[i]));
    }

    return res;
}

signed main()
{
    cin >> M >> N;
    rep(i, N) cin >> C[i];

    sort(C, C + N);

    sieve();
    fill(memo, memo + 10001, -1);

    can_make[0] = true;
    for (int i = 0; i < N; ++i) {
        for (int j = C[i]; j <= M; ++j) {
            can_make[j] = can_make[j] || can_make[j - C[i]];
        }
    }

    rep(i, M + 1) memo[i] = calc(i);

    int ans = 0;

    for (int i = M; i >= 0; --i) {
        if (is_prime[i] && can_make[M - i]) {
            ans += calc(M - i);
        }
    }

    ans += *max_element(memo, memo + 10001);

    cout << ans << endl;
}