#include <fstream>
#include <cmath>
using namespace std;
ifstream in("sume.in");
ofstream out("sume.out");
int main()
{
    long int n,m=1,s=1,i;
    in>>n;
    while (s<n)
    {
        s=s+m;
        m++;
    }
    long int a[n],b[m];
    for (i=1;i<=n;i++)
        in>>a[i];
    out<<m<<endl;
    b[1]=( a[1]+a[2]-a[m])/2;
    out<<b[1];
    for (i=2;i<=m;i++)
    {
        b[i]=a[i-1]-b[1];
        out<<" "<<b[i];
    }
    return 0;
}