#include <bits/stdc++.h>

using namespace std;

ifstream fin("reguli.in");
ofstream fout("reguli.out");
int n, i, j, p[500002], r;
long long v[500002], u, x;

int main() {
    fin >> n;
    fin >> u;
    for(i = 2; i <= n; i++) {
        fin >> x;
        v[i - 1] = (long long)(x - u);
        u = x;
    }

    for(i = 2; i < n; i++) {
        while(j > 0 && v[i] != v[j + 1]) j = p[j - 1];

        if(v[i] == v[j + 1]) j++;

        p[i] = j;
    }

    fout << n - 1 - p[n - 1] << "\n";
    for(i = 1; i <= n - 1 - p[n - 1]; i++) fout << v[i] << "\n";

    return 0;
}