fruit

fruit = str(input())
day = str(input())
quantity = float(input())
days = [['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'], ['Saturday', 'Sunday']]
total_price = 0
prices = {"banana": [2.5, 2.7], 'apple': [1.2, 1.25], 'kiwi': [2.7, 3], 'orange': [0.85, 0.9],
          'grapefruit': [1.45, 1.6], 'pineapple': [5.5, 5.6],
          'grapes': [3.85, 4.2]}

if fruit in prices:
    if day in days[0]:
        total_price = quantity * prices[fruit][0]
    elif day in days[1]:
        total_price = quantity * prices[fruit][1]

if total_price == 0:
    print('error')
else:
    print(f'{total_price:.2f}')