#include <iostream>
#include <fstream>
using namespace std;
ifstream f("reguli.in");
ofstream g("reguli.out");
int v[500001],n,x,y,urm[500001];
int main()
{
    int i;
    f>>n;
    f>>x;
    for(i=2;i<=n;i++)
    {
        f>>y;
        v[i-1]=y-x;
        x=y;
    }
    n--;
    int k=0;
    for(i=2;i<=n;i++)
    {
        while(k!=0&&v[k+1]!=v[i]) k=urm[k];
        if(v[k+1]==v[i])k++;
        urm[i]=k;
    }

    g<<n-urm[n]<<'\n';
    for(i=1;i<=n-urm[n];i++)
        g<<v[i]<<" ";
    return 0;
}