#include <fstream>

using namespace std;
ifstream f("reguli.in");
ofstream g("reguli.out");
int t,x,i1,y,v[500010],k,i,p[500010];
int main()
{
    f>>t;
    f>>x;
    for(i1=2;i1<=t;i1++)
        {f>>y;
        v[i1-1]=y-x;
        x=y;
        }
    k=0;
    for(i=2;i<=t;i++)
    {
        for(;k!=0&&v[k+1]!=v[i];) k=p[k];
        if(v[k+1]==v[i]) k++;
        p[i]=k;
    }
    g<<t-1-p[t-1]<<'\n';
    for(i=1;i<=t-1-p[t-1];i++)
        g<<v[i]<<'\n';
    return 0;
}