fruit_shop_2

fruit = input()
day = input()
amount = float(input())
valid = False
if day == "Monday" or day == "Tuesday" or day == "Wednesday" or day == "Thursday" or day == "Friday" or\
        day == "Saturday" or day == "Sunday":
    valid = True
    weekend = day[0] == "S"

if valid:
    if fruit == "banana":
        price = 2.7 if weekend else 2.5
    elif fruit == "apple":
        price = 1.25 if weekend else 1.2
    elif fruit == "orange":
        price = 0.90 if weekend else 0.85
    elif fruit == "grapefruit":
        price = 1.6 if weekend else 1.45
    elif fruit == "kiwi":
        price = 3.0 if weekend else 2.7
    elif fruit == "pineapple":
        price = 5.6 if weekend else 5.5
    elif fruit == "grapes":
        price = 4.2 if weekend else 3.85
    else:
        valid = False
print(f"{amount * price:.2f}" if valid else "error")