Sum of Right Leaves

Given a binary tree root, return the sum of all leaves that are right children.

Constraints

• n ≤ 100,000 where n is the number of nodes in root

https://binarysearch.com/problems/Sum-of-Right-Leaves

Examples

Example 1

Input

• root =

Output

• answer = 2

Example 2

Input

• root =

Output

• answer = 10

Explanation

Since 7 + 3 = 10.

Solution