from decimal import Decimal

L = int(eval(input()))

print((Decimal(L/3)**3))

L = int(eval(input()))

print(((L/3)**3))
from decimal import Decimal

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

L = int(eval(input()))
print(((L / 3) ** 3))

-from decimal import Decimal - -print((Decimal(L / 3) ** 3)) +print(((L / 3) ** 3))