#include <bits/stdc++.h>
using namespace std;
ifstream f("reguli.in");
ofstream g("reguli.out");
// #define f cin
// #define g cout
long long n, x, v[500005], pr[500005];
int main()
{
    f >> n >> x;
    for (int i = 1, y; i < n; i++)
    {
        f >> y;
        v[i] = y - x;
        x = y;
    }
    for (int i = 2; i < n; i++)
    {
        pr[i] = pr[i - 1];
        while (pr[i] && v[i] != v[pr[i] + 1])
            pr[i] = pr[pr[i]];
        if (v[i] == v[pr[i] + 1])
            pr[i]++;
    }
    g << n - 1 - pr[n - 1] << '\n';
    for (int i = 1; i <= n - 1 - pr[n - 1]; i++)
        g << v[i] << '\n';
    return 0;
}