#include <fstream>
#include <vector>

using namespace std;

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

int main()
{
    int n, w = 0;
    in >> n;

    vector<int> v(n + 1);
    vector<int> nr(n + 1);
    vector<int> pi(n + 1);

    in >> v[1];
    for (int i = 2; i <= n; i++)
    {
        in >> v[i];
        nr[i - 1] = v[i] - v[i - 1];
    }

    for (int i = 2; i < n; i++)
    {
        while (w && nr[w + 1] != nr[i])
            w = pi[w];

        if (nr[w + 1] == nr[i])
            w++;

        pi[i] = w;
    }

    int lg = n - pi[n - 1] - 1;
    out << lg;

    out << '\n';

    for (int i = 1; i <= lg; i++)
        out << nr[i] << '\n';

    return 0;
}