#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>

#define REP(i,n) for(long (i)=0;(i)<(n);(i)++)
#define FOR(i,a,b) for(long (i)=(a);(i)<(b);(i)++)
#define RREP(i,a) for(long (i)=(a)-1;(i)>=0;(i)--)
#define FORR(i,a,b) for(long (i)=(a)-1;(i)>=(b);(i)--)
#define MOD 1000000007
#define PI acos(-1.0)
#define DEBUG(C) cout<<C<<endl;
#define VI vector<int>
#define VL vector<long>
#define VD vector<double>
#define PII pair<int,int>
#define PLL pair<long,long>
#define ALL(a) (a).begin(),(a).end()
#define SORT(a) sort((a).begin(),(a).end())
#define RSORT(a) sort((a).begin(),(a).end(),greater<int>())
#define MP(a,b) make_pair(a,b)
#define FORE(a,b) for(auto &&a:b)
#define INF 1e9

typedef long long LL;
typedef unsigned long long ULL;

using namespace std;

bool isPrime(int a){
    if(a<2) return false;
    for(int i=2;i*i<=a;i++){
        if(a%i==0) return false;
    }
    return true;
}

int M,N;
vector<int> C;
vector<int> dp;
int ans=0;

int main(){
    cin>>M>>N;
    C=vector<int>(N);
    REP(i,N) cin>>C[i];
    dp=vector<int>(M+1,-INF);
    dp[M]=0;
    REP(i,N){
        RREP(j,M-C[i]+1){
            dp[j]=max(dp[j],dp[j+C[i]]+1);
        }
    }
    int ans=0;
    RREP(i,M+1){
        //DEBUG(ans)
        if(isPrime(i)&&dp[i]>0) ans+=dp[i];
    }
    SORT(dp);
    ans+=dp.back(); cout<<ans<<endl;
}