input: Write a function to calculate the area of a circle by prompting the user to input the radius. The function should return the calculated area. If the given radius is zero or negative, the function should return "Invalid input".
  def calculate_circle_area():
      Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      if radius <= 0:
          return "Invalid input"
      area = Pi*radius**2
      return area
  
  assert calculate_circle_area()==113.04 if user enters 6
  assert calculate_circle_area()==113.04 if user enters 6
  assert calculate_circle_area()=="Invalid input" if user enters 0
  assert calculate_circle_area()=="Invalid input" if user enters -5
output: def calculate_circle_area():
      Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      if radius <= 0:
          return "Invalid input"
      area = Pi * radius ** 2
      return area