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

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

int dp[10001];
bool prime[10001];

int main(void) {
    int i, j, m, n;
    int c[20];
    cin >> m >> n;
    rep (i,n) cin >> c[i];

    REP (i,2,m+1) prime[i] = true;
    for (i = 2; i * i <= m; i++) if (prime[i]) {
        for (j = i * 2; j <= m; j+=i)
            prime[j] = false;
    }

    rep (i,m) dp[i] = -1;
    rep (i,n) rrep (j,m) if (j+c[i] <= m && dp[j+c[i]] >= 0)
        dp[j] = max(dp[j],dp[j+c[i]]+1);

    int ans = 0, mx = 0;
    rep (i,m) {
        if (prime[i] && dp[i] > 0)
            ans += dp[i];
        mx = max(mx,dp[i]);
    }
    ans += mx;
    cout << ans << endl;
    return 0;
}