#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;

int ans[10001];
bool is_prime[10001];
int main(){
    int m, n, max_ans=0;
    cin >> m >> n;
    vector<int> c(n);
    for(int i=0; i<n; ++i){
        cin >> c[i];
        if(c[i] < m){
            ++ans[c[i]];
            max_ans = 1;
        }
    }
    sort(c.begin(), c.end());
    for(int i=0; i<m; ++i){
        if(ans[i]){
            for(int j=0; j<n; ++j){
                if(i+c[j] <= m){
                    ans[i+c[j]] = max(ans[i+c[j]], ans[i]+1);
                    max_ans = max(max_ans, ans[i]+1);
                }
            }
        }
    }

    for(int i=0; i<=m; ++i){
        is_prime[i] = 1;
    }
    is_prime[0] = is_prime[1] = 0;

    int prime_n = (int)(sqrt(m)) + 1;
    for(int i=2; i<prime_n; ++i){
        if(is_prime[i]){
            for(int j=2; i*j<=m; ++j){
                is_prime[i*j] = 0;
            }
        }
    }

    for(int i=0; i<m; ++i){
        max_ans += is_prime[i] * ans[m-i];
    }

    cout << max_ans << endl;
}