Amin and Belal are two friends. Both have good knowledge about graph and tree in data structure part. Now they discuss about some problems of Codeforces which are related to these topics. Amin now figure out a binary tree which are consists of some nodes and edges. A binary tree is a tree in which each node has at most two children, which are referred to as the left child and the right child. The following figure contains a binary tree.
This is a companion discussion topic for the original entry at https://toph.co/p/identify-the-level