from math import floor

from decimal import Decimal





L = Decimal(eval(input()))

print((L**3/27))

l=int(eval(input()))

print((l**3/27))

from math import floor
from decimal import Decimal

L = Decimal(eval(input()))
print((L**3 / 27))

l = int(eval(input()))
print((l**3 / 27))

-from math import floor -from decimal import Decimal - -L = Decimal(eval(input())) -print((L**3 / 27)) +l = int(eval(input())) +print((l**3 / 27))