#include <bits/stdc++.h>
using namespace std;
#define int long long   // <-----!!!!!!!!!!!!!!!!!!!

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
#define rrep2(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define all(a) (a).begin(),(a).end()

typedef long long ll;
typedef pair<int, int> Pii;
typedef tuple<int, int, int> TUPLE;
typedef vector<int> V;
typedef vector<V> VV;
typedef vector<VV> VVV;
typedef vector<vector<int>> Graph;
const int inf = 1e9;
const int mod = 1e9 + 7;

// x > 0
bool isPrime(int n) {
    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0) return false;
    }
    return n != 1;
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int M, N;
    cin >> M >> N;
    V C(N);
    rep(i, N) cin >> C[i];

    V dp(M + 1, -inf);
    dp[M] = 0;
    rep(i, N) {
        for (int j = M - C[i]; j >= 0; j--) {
            dp[j] = max(dp[j], dp[j + C[i]] + 1);
        }
    }

    int ans = 0;
    rep2(i, 1, M) {
        if (dp[i] > 0 && isPrime(i)) {
            ans += dp[i];
        }
    }

    ans += *max_element(all(dp));
    cout << ans << endl;
}