Inserting in a binary search tree P94818

Write a program that forms a binary search tree from a given sequence of natural numbers. Each new integer must be placed at the only leaf that allows to mantain the propierty of the binary search trees. The repeated elements must be ignored.

Input

Input is a non empty sequence of natural numbers.

Output

Your program must print the resulting tree, following the same format of the instances (which is the same that the format of the exercise , but now with natural numbers).