# To Do

#Ask user for servings made by recipe (and check this is a number that is more that
#Ask user for servings desired (check this is a number)
#Calcualte the scale factor
#Warn the user if the sf is less than 0.25 or more than 4

#functions go here

# Number Checking Function
def num_check(question):

    error = "Please enter a number that is more than zero"

    valid = False
    while not valid:
        try:
             response = float(input(question))

             if response <= 0:
                 print(error)
             else:

                  return response

        except ValueError:
             print(error)

# Main Routine goes here

serving_size = num_check("What is the recipe serving size? ")
desired_size = num_check("How many servings are needed? ")

scale_factor = desired_size / serving_size

print("Scale Factor: {}".format(scale_factor))