#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
const int NMax=500005;
int N,X[NMax],A[NMax],K,P[NMax],q;

void Read()
{
    fin>>N;
    for(int i=0;i<N;++i)
    {
        fin>>X[i];
    }
    for(int i=1;i<N;++i)
    {
     A[i]=X[i]-X[i-1];
    }
}


void Make_prefix()
{
    for(int i=2;i<N;++i)
    {
        while(q && A[q+1]!=A[i])
        {
            q=P[q];
        }
        if(A[q+1]==A[i])
        {
            ++q;
        }
        P[i]=q;
         if(q && i%(i-q)==0)
            {
                K=i-q;
            }
    }
}

int main()
{
    Read();
    Make_prefix();
    fout<<K<<"\n";
    for(int i=1;i<=K;++i)
    {
        fout<<A[i]<<"\n";
    }
    return 0;
}