题解 | #求解立方根#

def bina(y, m, n):
    x = (m+n)/2
    cmp = x**3
    if abs(y - cmp) <= espi:
        ret = x
    elif y - cmp > espi:
        ret = bina(y, x, n)
    else:
        ret = bina(y, m, x)

    return ret


n = float(input())
espi = 1e-3
right = max(n, 1)
left = min(n, -1)

x = bina(n, left ,right)

print("{:.1f}".format(x))