#include <fstream>
#include <vector>

using namespace std;

int main()
{
    ifstream fin("reguli.in");
    ofstream fout("reguli.out");
    int n;
    fin >> n;
    vector <int> v(n);
    for (int i = 0;i < n;++i)
        fin >> v[i];
    vector <int> diff(n - 1);
    for (int i = 1;i < n;++i)
        diff[i - 1] = v[i] - v[i - 1];
    vector <int> pi(diff.size(), 0);
    for (int i = 1, k = 0;i < diff.size();++i)
    {
        for (;k > 0 && diff[k] != diff[i];k = pi[k - 1]);
        if (diff[i] == diff[k])
            ++k;
        pi[i] = k;
    }
    int p = n - 1 - pi.back();
    fout << p << "\n";
    for (int i = 0;i < p;++i)
        fout << diff[i] << "\n";
    fin.close();
    fout.close();
    return 0;
}