猜数字事先给定一个数字，然后让用户猜3次，猜不中就输了，猜中就赢了。每次猜错，给出提示，less or big

c = 0
a = 10

while c <3:
    b = int(raw_input("请输入数字"))
    if b == a:
        print "你赢了"
        break
    else:
        print "les or big"
    c = c + 1