while True:
    try:
        x = float(input())
        if x==0:
            print(0)
            break
        if x>0:
            sig =1
        else:
            sig =-1
        x = abs(x)
         
        if x>1:
            low,high = 1,x
        else:
            low,high =x,1
            
        while (low <= high):
            mid = (low+high)/2
            if abs(mid**3 -x)<=0.01:
                print(round(sig*mid,1))
                break
            elif mid**3 -x <0:
                low = mid
            elif mid**3 -x >0:
                high = mid
    except:
        break