#include <iostream>
#include <fstream>
using namespace std;

ifstream F("reguli.in");
ofstream G("reguli.out");

const int N = 500010;

long long x,y,a[N];
int n,pi[N];

void build()
{
    int p = 0;
    for (int i=2;i<=n;++i)
    {
        while ( p != 0 && a[p+1] != a[i] )
            p = pi[p];
        if ( a[i] == a[p+1] )
            ++p;
        pi[i] = p;
    }
}

int main()
{
    F>>n>>x;
    --n;

    for (int i=1;i<=n;++i)
    {
        F>>y;
        a[i] = y-x;
        x = y;
    }

    build();

    int len = n-pi[n];
    G<<len<<'\n';
    for (int i=1;i<=len;++i)
        G<<a[i]<<'\n';
}