Solve the programming task below in a Python markdown code block.
A pair of nodes, $(a,b)$, is a similar pair if the following conditions are true:

node $a$ is the ancestor of node $b$
$abs(a-b)\leq k$

Given a tree where each node is labeled from $1$ to $n$, find the number of similar pairs in the tree.

For example, given the following tree:  

We have the following pairs of ancestors and dependents:  

Pair	abs(a-b)	Pair	abs(a-b)
1,2	1		3,4	1
1,3	2		3,5	2
1,4	3		3,6	3
1,5	4
1,6	5

If $k=3$ for example, we have $6$ pairs that are similar, where $abs(a-b)\leq k$.

Function Description

Complete the similarPair function in the editor below.  It should return an integer that represents the number of pairs meeting the criteria.

similarPair has the following parameter(s):  

n: an integer that represents the number of nodes  
k: an integer
edges: a two dimensional array where each element consists of two integers that represent connected node numbers  

Input Format

The first line contains two space-separated integers $n$ and $k$, the number of nodes and the similarity threshold. 

Each of the next $n-1$ lines contains two space-separated integers defining an edge connecting nodes $p[i]$ and $c[i]$, where node $p[i]$ is the parent to node $c[i]$.

Constraints

$1\leq n\leq10^5$  
$0\leq k\leq n$  
$1\leq p[i],c[i]\leq n$  

Output Format

Print a single integer denoting the number of similar pairs in the tree.

Sample Input
5 2
3 2
3 1
1 4
1 5

Sample Output
4

Explanation

The similar pairs are $(3,2)$, $(3,1)$, $(3,4)$, and $(3,5)$, so we print $4$ as our answer. 

Observe that $(1,4)$ and $(1,5)$ are not similar pairs because they do not satisfy $abs(a-b)\leq k$ for $k=2$.