#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  if (a == 0)
    return b;
  else
    return gcd(b % a, a);
}
int be(int a, int b) {
  int ans = 1;
  while (b) {
    if (b & 1) {
      b--;
      ans *= a;
      ans %= 1000000007;
    }
    b /= 2;
    a *= a;
    a %= 1000000007;
  }
  return ans;
}
void fi(int &num) {
  bool neg = false;
  num = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') break;
    ch = getchar();
  }
  if (ch == '-') {
    neg = true;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    num = num * 10 + ch - '0';
    ch = getchar();
  }
  if (neg) num = -num;
}
int add(int a, int b) {
  int sum = a % 1000000007;
  sum += (b % 1000000007);
  sum %= 1000000007;
  if (sum < 0) sum += 1000000007;
  return sum;
}
int mul(int a, int b) {
  int ans = a % 1000000007;
  ans *= (b % 1000000007);
  ans %= 1000000007;
  return ans;
}
int n;
int arr[1001];
vector<int> ans;
signed main() {
  scanf("%d", &n);
  int c = 0;
  bool hua = false;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &arr[i]);
    if (i == 1) {
      ans.push_back(arr[1]);
      continue;
    }
    if (gcd(arr[i], ans[ans.size() - 1]) == 1) {
      ans.push_back(arr[i]);
    } else {
      ans.push_back(1);
      ans.push_back(arr[i]);
      c++;
    }
  }
  printf("%d\n", c);
  for (int i = 0; i < ans.size(); i++) printf("%d ", ans[i]);
  return 0;
}
