Description
Once upon a time, Camo found that a binary search tree is a very powerful tool, so she wants to build it to support her job, could you help her?
There are two instructions below with the description:
1. Insert num
Insert a number into the binary tree. If the number is already in the binary tree, skip it.
2. Print
Print the binary tree in pre-order
This is a partial judge problem, you're asked to implement these 2 functions.
Input
The input consists of multiple instructions (1 ≤ number of instructions ≤ 105)
the number of each instruction is a positive integer and not greater than 109.
Output
The output only consists of a line denoting the pre-order binary tree after every Print instruction.
It's guaranteed that for every Print instruction, the tree is not empty.