#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
bool isPrime(int x) {
  if (x % 2 == 0) return 0;
  int s = sqrt(x);
  for (int i = 3; i <= s; i += 2)
    if (x % i == 0) return 0;
  return 1;
}
int main() {
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) cin >> arr[i];
  int c = 0;
  for (int i = 1; i < n; i++) {
    int g = gcd(arr[i], arr[i - 1]);
    if (g != 1) c++;
  }
  cout << c << endl << arr[0] << " ";
  for (int i = 1; i < n; i++) {
    if (gcd(arr[i], arr[i - 1]) != 1) cout << 1 << " ";
    cout << arr[i] << " ";
  }
  return 0;
}
