#include <library.h>

// length of a Collatz sequence

void main()
{ cout << "Enter starting value: ";
  int n = read_int();
  int length = 0;
  while (true)
  { cout << n << "\n";
    length = length + 1;
    if (n == 1)
      break;
    if (n % 2 == 0)
      n = n / 2;
    else
      n = n * 3 + 1; }
  cout << "Length of sequence = " << length << "\n"; }