#include <bits/stdc++.h>
using namespace std;
bool arr[1000][1000], vis[1000001], check;
vector<int> sol, inds;
unsigned int mx;
int n, sz;
bool is_prime(int x) {
  for (int i = 2; i * i <= x; i++)
    if (x % i == 0) return 0;
  return 1;
}
void max_array(int ind) {
  inds.push_back(ind);
  for (int i = 0; i < n; i++)
    if (arr[ind][i]) {
      sz = inds.size();
      check = 1;
      for (int j = 0; j < sz; j++)
        if (!arr[inds[j]][i]) {
          check = 0;
          break;
        }
      if (check) max_array(i);
    }
  if (inds.size() > mx) {
    mx = inds.size();
    sol = inds;
  }
  inds.pop_back();
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int cnt_one = -1;
  cin >> n;
  int x[n];
  for (int i = 0; i < n; i++) {
    cin >> x[i];
    cnt_one += (x[i] == 1);
    if (!vis[x[i]])
      vis[x[i]] = 1;
    else {
      n--;
      i--;
    }
  }
  sort(x, x + n);
  for (int i = 0; i < n - 1; i++)
    for (int j = i + 1; j < n; j++)
      if (is_prime(x[i] + x[j])) arr[j][i] = arr[i][j] = 1;
  for (int i = 0; i < n; i++) max_array(i);
  if (x[sol[0]] != 1 && cnt_one + 1 > mx) {
    cout << cnt_one + 1 << '\n';
    for (int i = -1; i < cnt_one; i++) cout << 1 << ' ';
  } else {
    if (x[sol[0]] == 1) {
      cout << mx + cnt_one << '\n';
      for (int i = 0; i < cnt_one; i++) cout << 1 << ' ';
    } else
      cout << mx << '\n';
    for (unsigned int i = 0; i < sol.size(); i++) cout << x[sol[i]] << ' ';
  }
  return 0;
}
