#include <iostream>
#include <fstream>

using namespace std;

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

const int N = 500010;

int n, x, y, d[N], pi[N];

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

    int k = 0;
    for(int i=2; i<n; i++)
    {
        while(k && d[k+1] != d[i])
            k = pi[k];
        if(d[k+1] == d[i]) k++;
        pi[i] = k;
    }
    n = n - pi[n-1] - 1;
    fout<<n<<'\n';
    for(int i=1; i<=n; i++)
        fout<<d[i]<<'\n';

    return 0;
}