Vegetable Market

priceVegetables = float(input())
priceFruits = float(input())
quantityVegetables = float(input())
quantityFruits = float(input())

sumVegetables = priceVegetables*quantityVegetables
sumFruits = priceFruits*quantityFruits

totalSum = sumFruits+sumVegetables

sumInEuro = (totalSum / 1.94)
print(f"{sumInEuro:.15n}")