import numpy as np

L = np.array(int(eval(input())), dtype='float128')

ans = (L / 3)**3

print(ans)

import numpy as np

L = int(eval(input()))

ans = (L / 3)**3

print(ans)

import numpy as np

L = np.array(int(eval(input())), dtype="float128")
ans = (L / 3) ** 3
print(ans)

import numpy as np

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

-L = np.array(int(eval(input())), dtype="float128") +L = int(eval(input()))