# include <fstream>
# define DIM 500010
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
long long v[DIM],n,s,x,i,j,t,ok;
int main () {
    fin>>n;
    n--;
    for(i=0;i<=n;i++){
        fin>>x;
        v[i]=x-s;
        s=x;
    }
    for(i=1;i<=n;i++){
        ok=1;
        for(j=1;j<=n&&ok;j+=i)
            for(t=j;t<min(j+i,n+1)&&ok;t++)
                if(v[t]!=v[t-j+1])
                    ok=0;
        if(ok){
            fout<<i<<"\n";
            for(j=1;j<=i;j++)
                fout<<v[j]<<"\n";
            return 0;
        }
    }
    return 0;
}