python递归

n = int(input())
a = 'A'
b = 'B'
c = 'C'
def sbliuxin(a, b, c, n):
if n == 1:
print(a,'->',b)
return
sbliuxin(a,c, b, n - 1)
print(a,'->',b)
sbliuxin(c, b, a, n - 1)

sbliuxin(a,c,b,n)