trade_commmissions

city = input()
sales = float(input())
result = 0

if city == "Sofia":
    if sales >= 0 and sales <=500:
        result = sales * 0.05
    elif sales > 500 and sales <= 1000:
        result = sales * 0.07
    elif sales > 1000 and sales <= 10000:
        result = sales * 0.08
    elif sales > 10000:
        result = sales * 0.12
elif city == "Varna":
    if sales >= 0 and sales <=500:
        result = sales * 0.045
    elif sales > 500 and sales <= 1000:
        result = sales * 0.075
    elif sales > 1000 and sales <= 10000:
        result = sales * 0.10
    elif sales > 10000:
        result = sales * 0.13
elif city == "Plovdiv":
    if sales >= 0 and sales <=500:
        result = sales * 0.055
    elif sales > 500 and sales <= 1000:
        result = sales * 0.08
    elif sales > 1000 and sales <= 10000:
        result = sales * 0.12
    elif sales > 10000:
        result = sales * 0.145
else:
    result = "error"
if type(result) == str or sales < 0:
    print("error")
else:
    print(f"{result:.2f}")