题解 | #求解立方根#

a=float(input())
b=1
if a<0:
    b=-1
    a=a*b
for i in range(20):
    if i*i*i<=a and a<(i+1)*(i+1)*(i+1):
        break
for n in range(1000):
    if (n*0.001+i)*(n*0.001+i)*(n*0.001+i)<=a and ((n+1)*0.001+i)*((n+1)*0.001+i)*((n+1)*0.001+i)>a:
        res=n*0.001+i
#print(res)
if b==1:

    print(round(res,1))
else:
    print(round(res*-1,1))