from math import *
x = 0
z = 0
y = 0
k = 0
senh = (x / factorial(1)) * k
x = float
while(senh != k):
	x=float(input("x: "))
	k = int(input("k: "))
	senhx = senh * (x**2 / 1 + 2)
	
	print(round(senh, 9))