题解 | #求解立方根#

import sys

data=float(sys.stdin.readline())
fushu=0

data=int(1000*data)
if data<0:
    data=abs(data)
    fushu=1

min1=0
max1=0

for i in range(int(data)):
    # print(i)
    if i*i*i>int(data):
        min1=i-1
        max1=i
        break


if abs(min1**3-data)<abs(max1**3-data) and fushu==0:

    print(min1/10)
elif abs(max1**3-data)<abs(min1**3-data) and fushu==1:
    print(max1/10*-1)

elif abs(min1**3-data)<abs(max1**3-data) and fushu==1:

    print(min1/10*-1)

else:
    print(max1/10)