有一个黑箱子，里面会按升序存储整数，你可以对黑箱子下达下面的指令：

a. ADD n 将n加入黑箱子

b. Get 获得一个数，这个数在黑箱子里的序号（从0开始计数）是Get的出现次数。

黑箱子中最初存了一个数0，现给你一个操作序列，要你输出Get命令时获的那个数。

-There is a black box, which will store the integers in ascending order, you can order black box issued the following: a. ADD n to n by adding a black box b. Get access number, the serial number of houses in the black box (from start counting with 0) is the number of occurrences Get. Initially stored in the black box, a number 0, is to give you a sequence of operations, to you Get out of that number by the command.