fruit_shop_3

prices = {
    "banana": [2.50, 2.70],
    "apple": [1.20, 1.25],
    "orange": [0.85, 0.90],
    "grapefruit": [1.45, 1.60],
    "kiwi": [2.70, 3.00],
    "pineapple": [5.50, 5.60],
    "grapes": [3.85, 4.20]
}

days_of_the_week = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]

try:
    fruit_prices = prices[input()][days_of_the_week.index(input()) // 5]
    print(f"{fruit_prices * float(input()):.2f}")
except (KeyError, ValueError):
    print("error")