#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];
int dp[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;
        }
    }
}

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

    sort(C, C + N);

    sieve();

    fill(dp, dp + 10001, -1);
    dp[0] = 0;

    rep(i, N) {
        for (int j = C[i]; j <= M; ++j) {
            if (~dp[j - C[i]]) {
                dp[j] = max(dp[j], dp[j - C[i]] + 1);
            }
        }
    }

    int ans = *max_element(dp, dp + 10001);

    for (int i = M - 1; i >= 0; --i) {
        if (is_prime[i] && ~dp[M - i]) {
            ans += dp[M - i];
        }
    }

    cout << ans << endl;
}