#include <fstream>
#include <cstring>
using namespace std;
int pi[500002];
long long v[500002];
int main()
{
    int n,k,i;
    ifstream in("reguli.in");
    ofstream out("reguli.out");
    in>>n;
    for(i=0;i<n;i++)
    {
        in>>v[i];
    }
    for(i=n-1;i>0;i--)
        v[i]-=v[i-1];
    k=0;
    for(i=2;i<n;i++)
    {
        in>>v[i];
        while(v[i]!=v[k+1]&&k>0)
        {
            k=pi[k];
        }
        if(v[i]==v[k+1])
            k++;
        pi[i]=k;
    }
    k=n-k-1;
    out<<k<<"\n";
    for(i=1;i<=k;i++)
    {
        out<<v[i]<<"\n";
    }
    return 0;
}