/// Preset de infoarena
#include <fstream>

using namespace std;

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

int n, pred, curr, v[500005], pi[500005];

int main()
{
    fin >> n >> pred;
    for(int i = 1; i < n; i++)
    {
        fin >> curr;
        v[i] = curr - pred;
        pred = curr;
    }
    for(int i = 2; i < n; i++)
    {
        int k = pi[i - 1];
        while(k && v[i] != v[k + 1])
            k = pi[k];
        if(v[i] == v[k + 1])
            k++;
        pi[i] = k;
    }
    int ans = n - pi[n - 1] - 1;
    fout << ans << '\n';
    for(int i = 1; i <= ans; i++)
        fout << v[i] << '\n';
    return 0;
}