total = 1.5
response = input("Do you want fries with your order? ")
if response.lower().startswith('y'):
    #they want fries, what what size?
    response = input("What size? (small, medium, or large) ")
    if response.lower() == 'small':
        total += 0.5
        print("small")
    elif response.lower() == 'medium':
        total += 0.75
        print("medium")
    elif response.lower() == 'large':
        total += 1
        print("large")
    else:
        print("Invalid size.")