题解 | #求解立方根#

# 20240919
f = float(input())
#print(f)
if f < 0:
    flag = -1
elif f > 0:
    flag = 1
else:
    flag = 0

if flag == 0:
    print(0.0)
else:
    f = abs(f)        # 从这里开始，f已经变成一个正整数了
    if f >= 1:
        left = 1
        right =f
    else:
        left = f
        right = 1
    mid = (left+right)/2
    while abs(mid*mid*mid -f) > 0.001:
        if mid ** 3 > f:
            right = mid
        else:
            left = mid
        mid = (left+right)/2
    print(round(mid*flag,1))