//ALEXANDRU MICLEA

#include <vector>
#include <algorithm>
#include <string>
#include <string.h>
#include <cstring>
#include <queue>
#include <map>
#include <set>
#include <unordered_map>
#include <time.h>
#include <iomanip>
#include <deque>
#include <math.h>
#include <cmath>
#include <assert.h>
#include <stack>
#include <bitset>
#include <random>
#include <chrono>
#include <assert.h>

using namespace std;
using ll = long long;

#include <fstream>
//ifstream cin("input.in"); ofstream cout("output.out");
ifstream cin("reguli.in"); ofstream cout("reguli.out");


//VARIABLES

string a, b;



//FUNCTIONS



//MAIN

int main() {

    int t; cin >> t;
    vector <ll> v(t);
    vector <ll> pass(t - 1);
    
    for (auto& x : v) cin >> x;

    for (int i = 0; i < t - 1; i++) {
        pass[i] = v[i + 1] - v[i];
    }

    ll n = pass.size();
    vector<ll> pi(n);

    int ans = 0;
    for (int i = 1; i < n; i++) {
        ll j = pi[i - 1];
        while (j > 0 && pass[i] != pass[j]) j = pi[j - 1];
        if (pass[i] == pass[j]) j++;
        pi[i] = j;
    }


    cout << n - pi[n - 1] << '\n';
    for (int i = 0; i < n - pi[n - 1]; i++) cout << pass[i] << '\n';


    return 0;
}