06. Fishland

mackerel_price = float(input())
sprat_price = float(input())
bonito_fish_kg = float(input())
saffron_kg = float(input())
shell_kg = float(input())

bonito_fish_sum = bonito_fish_kg * mackerel_price * 1.60
saffron_sum = saffron_kg * sprat_price * 1.80
shell_sum = shell_kg * 7.50
sum = bonito_fish_sum + saffron_sum + shell_sum
print(f'{sum:.2f}')