input: Write a function to calculate the factorial of a given integer, and print the result. If the given integer is less than or equal to 1, the function should return 1.
  
  def factorial(num):
      if num <= 1:
          return 1
      else:
          return num * factorial(num - 1) 
  
  n = int(input("Enter a number: "))  
  print("Factorial of",n,"is",factorial(n))
output: def factorial(num):
      if num <= 1:
          return 1
      else:
          return num * factorial(num - 1)