#include<stdio.h>
#include<iostream>
using namespace std;
long long a[500005];
int main()
{
freopen("reguli.in","r",stdin);
freopen("reguli.out","w",stdout);
unsigned n,m,i,j;
cin>>n;
n--;
for(i=0;i<=n;i++)
 cin>>a[i];
for(i=n;i>0;i--)
    a[i]=a[i]-a[i-1];
m=j=1;
for(i=2;i<=n;i++)
   {
       if(a[i]==a[j])
       {
           j++;
           if(j>m)
            j=1;
       }
       else
       {
           m=i;
           j=1;
       }
   }
  cout<<m<<"\n";
   for(i=1;i<=m;i++)
    cout<<a[i]<<"\n";
    return 0;
}