fruit = (input())
day = (input())
piece = float(input())
price = 0

if day == 'Monday' or day == 'Tuesday' or day == 'Wednesday' or day == 'Thursday' or day == 'Friday':
    if fruit == 'banana':
        price = piece * 2.50
    elif fruit == 'apple':
        price = piece * 1.20
    elif fruit == 'orange':
        price = piece * 0.85
    elif fruit == 'grapefruit':
        price = piece * 1.45
    elif fruit == 'kiwi':
        price = piece * 2.70
    elif fruit == 'pineapple':
        price = piece * 5.50
    elif fruit == 'grapes':
        price = piece * 3.85
elif day == 'Saturday' or day == 'Sunday':
    if fruit == 'banana':
        price = piece * 2.70
    elif fruit == 'apple':
        price = piece * 1.25
    elif fruit == 'orange':
        price = piece * 0.90
    elif fruit == 'grapefruit':
        price = piece * 1.60
    elif fruit == 'kiwi':
        price = piece * 3.00
    elif fruit == 'pineapple':
        price = piece * 5.60
    elif fruit == 'grapes':
        price = piece * 4.20

if price == 0:
    print("error")
else:
    print(f"{price:.2f}")