python小游戏：石头剪刀布

import random

pc = random.randint(1, 3)
a = None
if pc == 1:
    a = "石头"
elif pc == 2:
    a = "剪刀"
else:
    a = "布"

player = input("请输入剪刀石头布：")
if a == "石头" and player == "剪刀" or a == "剪刀" and player == "布" or a == "布" and player == "石头":
    print("电脑出了%s,我出了%s,电脑赢了" % (a, player))

elif a == player:
    print("电脑出了%s,我出了%s,平局" % (a, player))

else:
    print("电脑出了%s, 我出了%s, 我赢了" % (a, player))