#include <bits/stdc++.h>
#define EPS 1e-9
#define INF 1070000000LL
#define MOD 1000000007LL
#define fir first
#define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++)
#define numa(x,a) for(auto x: a)
#define ite iterator
#define mp make_pair
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define pb push_back
#define pf push_front
#define sec second
#define sz(x) ((int)(x).size())
#define ALL( c ) (c).begin(), (c).end()
#define gcd(a,b) __gcd(a,b)
#define mem(x,n) memset(x,n,sizeof(x))
#define endl "\n"
using namespace std;
template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}
template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }
template <class T,class U> std::ostream& operator<<(std::ostream &os, std::pair<T,U> &p){ os << "(" << p.first <<", " << p.second <<")";return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }
#define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; }
#define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); }
#define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); }
#define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); }
using ll = long long;

vector <int> Eratosthenes(int mynum){
  vector <bool> flag(mynum+1);
  vector <int> ans;
  rep2(i,2,mynum+1){
    if(!flag[i]){
      ans.pb(i);
      for(int j = 2 * i ; j <= mynum ; j += i){
	flag[j] = true;
      }
    }else{
      ;
    }
  }
  return ans;
}

int M, N;

ll memo[23][10010];
int main()
{
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  cin >> M;
  cin >> N;
  //int nums[23];
  set <int> n2;
  rep(i,N){
    int x;
    cin >> x;
    n2.insert(x);
  }
  vector <int> nums(sz(n2)+1);  
  int cnt = 1;
  numa(x,n2){
    nums[cnt++] = x;
  }
  N = sz(nums) - 1;
  memo[0][0] = 1;
  for (int i = 1; i <= N; i++) {//20
    for (int j = 0; j <= 10000; j++) {//10000
      if (memo[i-1][j] > 0) {
        for (int k = 0; j + nums[i] * k <= 10000; k++) {//j / nums[i]
          memo[i][j+nums[i]*k] = max(memo[i][j+nums[i]*k], memo[i-1][j] + k);
        }
      }
    }
  }
  auto primes = Eratosthenes(M);
  ll ans = 0;
  numa(p, primes){
    int target = M - p;
    if (target >= 0 && memo[N][target] > 1) {
      //DEBUG2(target ,memo[N][target] - 1);
      ans += memo[N][target] - 1;
    }
  }
  ll ret = 0;
  for (int i = 0; i <= M; i++) {
    if (memo[N][i] > 1) {
      ret = max(ret, memo[N][i] - 1);
    }
  }
  cout << ans+ret << endl;
  return 0;
}