Package for this problem was not updated by the problem writer or Codeforces administration after we’ve upgraded the judging servers. To adjust the time limit constraint, solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then value 800 ms will be displayed and used to determine the verdict.

Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

E. Close Vertices

time limit per test

5 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou've got a weighted tree, consisting of *n* vertices. Each edge has a non-negative weight. The length of the path between any two vertices of the tree is the number of edges in the path. The weight of the path is the total weight of all edges it contains.

Two vertices are close if there exists a path of length at most *l* between them and a path of weight at most *w* between them. Count the number of pairs of vertices *v*, *u* (*v* < *u*), such that vertices *v* and *u* are close.

Input

The first line contains three integers *n*, *l* and *w* (1 ≤ *n* ≤ 10^{5}, 1 ≤ *l* ≤ *n*, 0 ≤ *w* ≤ 10^{9}). The next *n* - 1 lines contain the descriptions of the tree edges. The *i*-th line contains two integers *p*_{i}, *w*_{i} (1 ≤ *p*_{i} < (*i* + 1), 0 ≤ *w*_{i} ≤ 10^{4}), that mean that the *i*-th edge connects vertex (*i* + 1) and *p*_{i} and has weight *w*_{i}.

Consider the tree vertices indexed from 1 to *n* in some way.

Output

Print a single integer — the number of close pairs.

Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.

Examples

Input

4 4 6

1 3

1 4

1 3

Output

4

Input

6 2 17

1 3

2 5

2 13

1 6

5 9

Output

9

Codeforces (c) Copyright 2010-2020 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Sep/21/2020 03:06:31 (f1).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|