#include<cstdio>

#include<cstring>

#include<cmath>

#include<vector>

#include<algorithm>

using namespace std;

const int maxn=+;

long long a[maxn];

long long gcd(long long a,long long b)

{

    if(b==) return a;

    return gcd(b,a%b);

}

int n;

int main()

{

    vector<long long>ans;

    scanf("%d",&n);

    for(int i=;i<=n;i++) scanf("%lld",&a[i]);

    ans.push_back(a[]);

    int cnt=;

    for(int i=;i<=n;i++)

    {

        long long tmp=gcd(a[i],ans[ans.size()-]);

        if(tmp==) ans.push_back(a[i]);

        else

        {

            cnt++;

            ans.push_back();

            ans.push_back(a[i]);

        }

    }

    printf("%d\n",cnt);

    for(int i=;i<ans.size();i++) printf("%lld ",ans[i]);

    printf("\n");

    return ;

}