#include <bits/stdc++.h>

using namespace std;

template <typename T, typename U>
inline bool chmax(T& x, U a) {
  return x < a && (x = a, 1);
}

const int MAXM = 10001;
bool not_prime[MAXM] = {true, true};
int M, N;
int C[20];
int dp[MAXM];

signed main() {
  for (int i = 2; i * i < MAXM; i++) {
    if (not_prime[i]) continue;
    for (int j = i * i; j < MAXM; j += i) {
      not_prime[j] = true;
    }
  }
  cin >> M >> N;
  for (int i = 0; i < N; i++) {
    cin >> C[i];
  }
  memset(dp, -1, sizeof(dp));
  dp[0] = 0;
  for (int i = 0; i < N; i++) {
    for (int j = 0; j + C[i] <= M; j++) {
      if (dp[j] < 0) continue;
      chmax(dp[j + C[i]], dp[j] + 1);
    }
  }
  int ret = max_element(dp, dp + MAXM)[0];
  for (int i = 0; i <= M; i++) {
    if (not_prime[i]) continue;
    if (dp[M - i] < 0) continue;
    ret += dp[M - i];
  }
  cout << ret << endl;
  return 0;
}