from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN



L =int(eval(input()))



ans = Decimal((L/3)**3)



print((float(round(ans, 10))))
L = float(eval(input()))



ans = float((L/3)**3)



print(ans)
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN

L = int(eval(input()))
ans = Decimal((L / 3) ** 3)
print((float(round(ans, 10))))

L = float(eval(input()))
ans = float((L / 3) ** 3)
print(ans)

-from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN - -L = int(eval(input())) -ans = Decimal((L / 3) ** 3) -print((float(round(ans, 10)))) +L = float(eval(input())) +ans = float((L / 3) ** 3) +print(ans)