Pool Day

import math

people = int(input())
entrance = float(input())
desk_chair = float(input())
umbrella = float(input())

entrance_price = people * entrance
desk_chair_price = math.ceil(people * 0.75) * desk_chair
umbrella_price = math.ceil(people / 2) * umbrella

print(f"{entrance_price + desk_chair_price + umbrella_price:.2f} lv.")