#include "library.h"

// length of Collatz sequence for any starting point.
// it also prints the seuence.

int print_sequence(int N)
{ print(N);
  print(" ");
  if (N == 1)
    return 1;
  if (N % 2 == 0)   // even
    return 1 + print_sequence(N/2);
  else
    return 1 + print_sequence(3*N+1); }

void test_it()
{ print("N ?");
  const int N = read_int();
  const int len = print_sequence(N);
  new_line();
  print("length = ");
  print(len);
  new_line();
  test_it(); }

void main()
{ test_it(); }