#include <bits/stdc++.h>
using namespace std;
bool gcd(long long a, long long b) {
  if (b == 0) return a == 1;
  return gcd(b, a % b);
}
long long creat(long long a, long long b) {
  for (long long i = 1;; i++) {
    if (gcd(a, i) && gcd(b, i)) return i;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  short n;
  long long v[1001], v2[2004], j = 0;
  cin >> n;
  for (short i = 0; i < n; i++) cin >> v[i];
  for (short i = 0; i < n - 1; i++) {
    v2[j++] = v[i];
    if (!gcd(v[i], v[i + 1])) v2[j++] = creat(v[i], v[i + 1]);
  }
  v2[j++] = v[n - 1];
  cout << j - n << endl;
  for (short i = 0; i < j; i++) cout << v2[i] << ' ';
}
