#include<bits/stdc++.h>
using namespace std;
vector< bool > get_prime(int n)
{
  vector< bool > prime(n + 1, true);  
  if(n >= 0) prime[0] = false;
  if(n >= 1) prime[1] = false;
  for(int i = 2; i * i <= n; i++) {
    if(prime[i]) {
      for(int j = i + i; j <= n; j += i) prime[j] = false;
    }
  }
  return(prime);
}

int main()
{
  int M, N;
  int dp[10001];
  fill_n(dp, 10001, -114514);
  
  cin >> M >> N;
  dp[M] = 0;
  while(N--) {
    int C;
    cin >> C;
    for(int j = M; j >= C; j--) {
      dp[j - C] = max(dp[j - C], dp[j] + 1);
    }
  }

  vector< bool > isprime = get_prime(M);
  int ret1 = 0, ret2 = 0;
  for(int i = 0; i <= M; i++) {
    if(isprime[i]) ret1 += max(0, dp[i]);
    ret2 = max(ret2, dp[i]);
  }
  cout << ret1 + ret2 << endl; 
}