#include <stdio.h>

#define FIN "reguli.in"
#define FOUT "reguli.out"
#define NMAX 500001
#define INF 0x3f3f3f3f

long long x[NMAX], a[NMAX];
int N;

int search (int k)
{
  for (int i = 1; i < k; ++ i)
    a[i % k] = x[i] - x[i-1];
  a[k] = x[k] - x[k-1];
  bool verif = true;
  for (int i = 1; i < N; ++ i)
    if (i % k)
      if (x[i] != x[i-1] + a[i % k])
       {
         verif = false;
         break;
       }
      else;
    else
      if (x[i] != x[i-1] + a[k])
       {
         verif = false;
         break;
       }
  if (verif)
    return 1;
  return 0;
}

int
 main ()
{
  freopen (FIN, "rt", stdin);
  freopen (FOUT, "wt", stdout);

  scanf ("%d", &N);
  for (int i = 0; i < N; ++ i)
    scanf ("%d", &x[i]);
  for (int i = 1; i <= N; ++ i)
    if (search (i))
     {
       printf ("%d\n", i);
       for (int j = 1; j <= i; ++ j)
         printf ("%lld\n", a[j]);
       break;
     }
  return 0;
}