#include <bits/stdc++.h>
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
int lps[2000001],i,j,v[500005],nr,t,n,x,sol[500005];
int a[500001],b;
void prefix()
{ int i,k=0,nr=0,p1;
for (i=2; i<n; i++)
{
while (k && a[k]!=a[i-1]) k=lps[k];
if (a[k]==a[i-1]) k++;
lps[i]=k;
 if(lps[i]!=0 && (i)%(i-lps[i])==0)
    {nr=lps[i];
     p1=i-lps[i]+1;
    }
}
fout<<nr<<'\n';
for(i=p1;i<=p1+nr-1;i++)
    fout<<a[i-1]<<'\n';
}
int main()
{ fin>>n;
   fin>>v[1];
  for(i=2;i<=n;i++)
  {fin>>v[i];
   a[i-2]=v[i]-v[i-1];
  }
  prefix();
    return 0;
}