#include <iostream>
#include <fstream>

#define NMAX 500005

using namespace std;

ifstream fin("reguli.in");
ofstream fout("reguli.out");

long long int a[NMAX],b[NMAX],x[NMAX],k,n;

int main()
{
    fin >> n;
    int i;
    for(i=1;i<=n;i++)
        fin >> a[i];
    for(i=2;i<=n;i++)
        b[i-1]=a[i]-a[i-1];
    n-=1;
    k=0;
    for(i=2;i<=n;i++)
    {
        while(k>0 and b[i]!=b[k+1])
            k=x[k];
        if(b[i]==b[k+1])k++;
        x[i]=k;
    }
    fout << n-x[n] << '\n';
    for(i=1;i<=n-x[n];i++)
        fout << b[i] << '\n';
    return 0;
}