#include <bits/stdc++.h>
using namespace std;
const int intf = 0x3f3f3f3f;
int a[1005];
bool pr(int x) {
  for (int i = 2; i * i <= x; i++) {
    if (x % i == 0) {
      return false;
    }
  }
  return true;
}
int main() {
  int n;
  cin >> n;
  int y = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] == 1) {
      y++;
    }
  }
  sort(a, a + n);
  if (n == 1) {
    cout << 1 << endl;
    cout << a[0] << endl;
  } else if (n == 2) {
    if (pr(a[0] + a[1])) {
      cout << 2 << endl;
      cout << a[0] << ' ' << a[1] << endl;
    } else {
      cout << 1 << endl;
      cout << a[0] << endl;
    }
  } else {
    int q = -1, w = -1;
    if (y > 1) {
      int x = -1;
      for (int i = y; i < n; i++) {
        if (pr(1 + a[i])) {
          x = a[i];
          break;
        }
      }
      if (x != -1) {
        cout << y + 1 << endl;
        for (int i = 0; i < y; i++) {
          cout << 1 << ' ';
        }
        cout << x << endl;
      } else {
        cout << y << endl;
        for (int i = 0; i < y; i++) {
          cout << 1;
          if (i != y - 1) cout << ' ';
        }
      }
    } else if (y == 1) {
      for (int i = y; i < n - 1; i++) {
        for (int j = i + 1; j < n; j++) {
          if (pr(a[i] + a[j])) {
            q = a[i];
            w = a[j];
            if (pr(1 + a[i]) && pr(1 + a[j])) {
              cout << 3 << endl;
              cout << 1 << ' ' << a[i] << ' ' << a[j] << endl;
              return 0;
            }
          }
        }
      }
      if (q != -1 && w != -1) {
        cout << 2 << endl;
        cout << q << ' ' << w << endl;
      } else {
        cout << 1 << endl;
        cout << a[0] << endl;
      }
    } else {
      for (int i = y; i < n - 1; i++) {
        for (int j = i + 1; j < n; j++) {
          if (pr(a[j] + a[i])) {
            q = a[i];
            w = a[j];
          }
        }
      }
      if (q != -1 && w != -1) {
        cout << 2 << endl;
        cout << q << ' ' << w << endl;
      } else {
        cout << 1 << endl;
        cout << a[0] << endl;
      }
    }
  }
  return 0;
}
