kilometers = int(input())
day_or_night = input()

price = 0

if kilometers >= 100:
    price = kilometers * 0.06
elif 20 <= kilometers < 100:
    price = kilometers * 0.09
else:
    tax = 0.7
    if day_or_night == "day":
        price = kilometers * 0.79 + tax
    else:
        price = kilometers * 0.9 + tax

print(f"{price:.2f}")