#include <fstream>
using namespace std;
long long a[500020];
int pi[500020];
int n,m;
void R()
{
   // freopen("reguli.in","r",stdin);
    //scanf("%d",&n);
    ifstream fin("reguli.in");
    long long p,x,i;
    //scanf("%d",&x);
    fin>>n>>x;
    for(i=1; i<n; i++)
    {
        p=x;
       // scanf("%d",&x);
       fin>>x;
        a[i]=x-p;
    }
    n--;

}

void Prefix()
{
    int i,k=0;
    pi[1]=0;
    for(i=2; i<=n; i++)
    {
        while(k>0 && a[k+1]!=a[i])
            k=pi[k];
        if(a[k+1]==a[i])
            k++;
        pi[i]=k;
    }

    m=n-pi[n];
}
int main()
{
    R();
    Prefix();
    //freopen("reguli.out","w",stdout);
    //printf("%d\n",m);
    ofstream fout("reguli.out");
    fout<<m<<"\n";
    for(int i=1; i<=m; i++)
        fout<<a[i]<<"\n";
        //printf("%d\n",a[i]);
    return 0;
}