#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
const int maxm = maxn * 4 + 10;
const int inf = 1e9;
const long long mod = 1e8 + 7;
int getint() {
  char c;
  while ((c = getchar()) && !(c >= '0' && c <= '9') && c != '-')
    ;
  int ret = c - '0', sgn = 0;
  if (c == '-') sgn = 1, ret = 0;
  while ((c = getchar()) && c >= '0' && c <= '9') ret = ret * 10 + c - '0';
  if (sgn) ret = -ret;
  return ret;
}
int gcd(int a, int b) {
  while (a && b) {
    if (a >= b)
      a %= b;
    else
      b %= a;
  }
  return a + b;
}
int a[maxn], vis[maxn];
int main() {
  int n = getint();
  for (int i = 1; i <= n; i++) a[i] = getint();
  memset(vis, 0, sizeof(vis));
  int ans = 0;
  for (int i = 2; i <= n; i++) {
    int temp = gcd(a[i], a[i - 1]);
    if (temp == 1) continue;
    vis[i] = 1;
    ans++;
  }
  cout << ans << endl;
  for (int i = 1; i <= n; i++) {
    if (vis[i]) cout << 1 << " ";
    cout << a[i] << " ";
  }
  cout << endl;
  return 0;
}
