35

skumriq_price = float(input())
caca_price = float(input())
palamud_kg = float(input())
safrid_kg = float(input())
midi_kg = float(input())

palamud_price = skumriq_price + skumriq_price * 0.6
safrid_price = caca_price + caca_price * 0.8
midi_price = 7.5

total_palamud = palamud_price * palamud_kg
total_safrid = safrid_price * safrid_kg
total_midi = midi_price * midi_kg

total_money = total_midi + total_safrid + total_palamud
print(f'{total_money:.2f}')