# 永豐金turning plan解答
###### tags: `自己玩`
## <font color = red>注意!!!重新開啟網頁會換數字</font>
http://www.sinopac.com/upload/event/turingplan/index.html

import numpy 
l = 0
a = int(input("how many stair:"))
for j in range(0,round(a/2)+1,1):
    l+=numpy.math.factorial(a-j)/numpy.math.factorial(j)/numpy.math.factorial(a-2*j)
print("有{0}中辦法".format(l))