#include <bits/stdc++.h>

using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
#define ll long long
const int Nmax = 500000 + 5;
ll a[Nmax], n, b[Nmax], p[Nmax], k;
int main()
{
    fin >> n;
    for(int i = 1; i <= n; ++i)fin >> a[i];

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