#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

void findPrime(int N, vector<bool>& isPrime)
{
    isPrime.assign(N+1, true);
    isPrime[0] = isPrime[1] = false;
    for(int i=2; i*i<=N; i++){
        if(isPrime[i]){
            for(int j=i; i*j<=N; j++){
                isPrime[i*j] = false;
            }
        }
    }
}

int main()
{
    int m, n;
    cin >> m >> n;
    vector<int> c(n);
    for(int i=0; i<n; ++i)
        cin >> c[i];

    vector<int> dp(m+1, -1);
    dp[m] = 0;
    for(int x=m; x>0; --x){
        if(dp[x] == -1)
            continue;
        for(int i=0; i<n; ++i){
            int y = x - c[i];
            if(y >= 0)
                dp[y] = max(dp[y], dp[x] + 1);
        }
    }

    vector<bool> isPrime;
    findPrime(m, isPrime);
    int sum = 0;
    int ans = 0;
    for(int i=0; i<=m; ++i){
        if(dp[i] != -1){
            if(isPrime[i])
                sum += dp[i];
            ans = max(ans, dp[i]);
        }
    }
    ans += sum;
    cout << ans << endl;

    return 0;
}