Postorder Traversal

Easyjavapythonccppjavascript

Given a binary tree in level-order form (integers and null, first token is the root), print its nodes in Left -> Right -> Root (postorder) order.

Input Format

The first line contains an integer M, the number of level-order tokens. The second line contains M space-separated tokens (integers or null). It is blank when M is 0.

Output Format

Print the postorder traversal values separated by single spaces, or an empty line for an empty tree.

Example 1

Input

3
1 2 3

Output

2 3 1

Explanation: The root is processed after both subtrees.

Input (stdin)

Output

Run your code to see output here...