price_strawberries = float(input())
quantity_bananas = float(input())
quantity_oranges = float(input())
quantity_raspberries = float(input())
quantity_strawberries = float(input())

# cena za qgodite
total_strawberries = quantity_strawberries * price_strawberries

#cena za malinite
price_raspberries = price_strawberries / 2
total_raspberries = quantity_raspberries * (price_strawberries / 2)

#cena za banani
price_bananas = price_raspberries - 0.8 * price_raspberries
total_bananas = quantity_bananas * price_bananas

#cena za portokali
price_oranges = quantity_raspberries - 0.4 * price_raspberries
total_oranges = quantity_oranges * price_oranges

expenses = total_strawberries + total_raspberries + total_bananas + total_oranges
print(expenses)