The password of Xiaoming's combination lock is 1□45, which is a multiple of 3. He has forgotten a number in the combination lock, how many times can he try at least to ensure that the combination lock can be opened.
小明密码锁的密码是1□45，这个数是3的倍数．他忘记了密码中的一个数字，他最少试多少次保证能打开这把密码锁．
<result>3</result>