#include <bits/stdc++.h>
using namespace std;

#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define ALL(x) (x).begin(), (x).end()
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
#define fst first
#define snd second
typedef vector<int> vi;typedef vector<vi> vvi;typedef pair<int,int> pii;typedef vector<pii> vpii;
typedef long long ll;

template<class T> inline bool amax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }

vector<int> sieve(int n) {
  vector<int> ret;
  if (n <= 2) return ret;
  vector<bool> ok(n / 2, true);
  ret.push_back(2);
  for (int i = 3; i < n; i += 2) {
    int i2 = i / 2;
    if (!ok[i2]) continue;
    ret.push_back(i);
    for (int j = i2 + i; j < n/2; j += i) ok[j] = false;
  }
  return ret;
}

void Main() {
  int M, N;
  scanf("%d", &M);
  scanf("%d", &N);
  vi C(N);
  rep(i, N) scanf("%d", &C[i]);

  vi dp(M+1, -1);
  dp[M] = 0;

  int ans = 0;
  rrep(i, M+1) if (dp[i] >= 0) {
    amax(ans, dp[i]);
    rep(j,N) {
      if (i-C[j] >= 0) amax(dp[i - C[j]], dp[i] + 1);
    }
  }

  forr(p, sieve(M)) if (dp[p] > 0) ans += dp[p];

  _p("%d\n", ans);
}
int main() { cin.tie(0); ios::sync_with_stdio(false); Main(); return 0; }