#include<fstream>
using namespace std;
ifstream f("reguli.in");
ofstream g("reguli.out");
int i,n,nr,v[500009],a[500009],urm[500009];
void prefix(int a[])
{
    int i,k=0;
    urm[1]=0;
    for(i=2;i<=n;++i)
    {
        while(k!=0&&a[i]!=a[k+1])
        k=urm[k];
        if(a[i]==a[k+1])
        ++k;
        urm[i]=k;
    }
}
int main()
{
    f>>n;
    for(i=1;i<=n;++i)
    f>>v[i];
    for(i=1;i<n;++i)
    a[i]=v[i+1]-v[i];
    --n;
    prefix(a);
    nr=n-urm[n];
    g<<nr<<'\n';
    for(i=1;i<=nr;++i)
    g<<a[i]<<'\n';
    return 0;

}