Binary Tree Paths

Given a binary tree, return all root-to-leaf paths as individual strings. The tree is represented in level order traversal where each value is separated by spaces and a missing (null) node is denoted by N. A path is constructed by concatenating node values from the root to a leaf, with the arrow symbol -> between consecutive values.

For example, the tree represented by the input:

1 2 3 N 5 N N

corresponds to the following binary tree:

    1
   / \
  2   3
   \
    5

The output in this case would be:

1->2->5
1->3

Your task is to read the tree from standard input, construct it, and then output all the root-to-leaf paths, each on a new line.

inputFormat

Input is read from standard input as a single line containing space-separated tokens representing the binary tree in level order traversal. Each token is either an integer (node value) or N to represent a null (missing) node. For example:

1 2 3 N 5 N N

outputFormat

Output the list of root-to-leaf paths. Each path should be printed on a separate line. Nodes in a path are connected by the string ->. If the tree is empty, do not output anything.

## sample

1 2 3 N 5 N N

1->2->5
1->3

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