#-------------------------------------------------------------------------------
#  Collatz2.py
#-------------------------------------------------------------------------------

def oddPart(n):
   """Returns the largest odd number dividing n """
   if n%2==1:
      return n;
   else:
      return oddPart(n//2)  # recursive call to oddPart()
# end oddPart()
      
def abreviatedCollatz(n):
   """ 
   Prints the Collatz sub-sequence obtained by dividing out all even factors 
   in a single step
   """
   while n != 1:
      print(n, end=", ")
      if n % 2 == 0:        # n is even
         n = oddPart(n)
      else:                 # n is odd
         n = 3*n + 1
   # end while
   print(n, end=".\n")
#end abreviatedCollatz()
   
# function main() -------------------------------------------------------------
def main():

   k = int(input('Enter an integer: '))
   print('The Abreviated Collatz sequence starting at', k, 'is:')
   abreviatedCollatz(k)

# end main()

# closing conditional ---------------------------------------------------------
if __name__=='__main__':

   main()

# end