text: def factorial(num):
      if num <= 1 :
          print('1 반환')
          return 1
      print('%d * %d! 호출'% (num, num-1))
      retVal = factorial(num-1)
  
      print('%d * %d!(=%d) 반환'% (num, num-1,retVal))
      return num * retVal
  print('\n5! = ',factorial(5))