You have already solved five problems; why not sing a song of "Old Words" under this great tree to express your feelings? The final problem is about this tree, and its description is very simple.
Given a rooted tree with $n$ nodes, labeled $1 \sim n$, where node $1$ is the root. Given a constant $k$. Given $Q$ queries, each query provides $x, y$. Calculate: $$\sum_{i \le x} depth(lca(i, y))^k$$
$lca(x, y)$ denotes the lowest common ancestor of node $x$ and node $y$ in the rooted tree. $depth(x)$ denotes the depth of node $x$, where the depth of the root is $1$. Since the answer can be very large, you only need to output the result modulo $998244353$.
Input
The input contains $n + Q$ lines. The first line contains three positive integers $n, Q, k$. For the next $n-1$ lines, each line contains a positive integer $f_i$ ($1 \le f_i \le n$), representing the parent of node $i$ (for $i = 2 \sim n$). The next $Q$ lines each contain two positive integers $x, y$ ($1 \le x, y \le n$), representing a query.
Output
The output contains $Q$ lines, each containing an integer representing the result modulo $998244353$.
Examples
Input 1
5 5 2 1 4 1 2 4 3 5 4 2 5 1 2 3 2
Output 1
15 11 5 1 6
Note
The input tree:
1 | \ 2 4 - 3 | 5
The depths of the nodes are $1, 2, 3, 2, 3$ respectively. For the first query $x = 4, y = 3$, it is easy to find: $lca(1, 3) = 1$ $lca(2, 3) = 1$ $lca(3, 3) = 3$ $lca(4, 3) = 4$ Thus $depth(1)^2 + depth(1)^2 + depth(3)^2 + depth(4)^2 = 1 + 1 + 9 + 4 = 15$.
Data Scale and Convention
| Test Case ID | $n$ Size | $Q$ Size | $k$ Size | Note |
|---|---|---|---|---|
| 1 | $n \le 2,000$ | $Q \le 2,000$ | $1 \le k \le 10^9$ | None |
| 2 | ||||
| 3 | ||||
| 4 | ||||
| 5 | $n \le 50,000$ | $Q \le 50,000$ | $1 \le k \le 10^9$ | There exists a node with depth $n$ |
| 6 | ||||
| 7 | ||||
| 8 | ||||
| 9 | $n \le 50,000$ | $Q = n$ | $1 \le k \le 10^9$ | For the $i$-th query, $x = i$ |
| 10 | ||||
| 11 | $n \le 50,000$ | $Q \le 50,000$ | $k = 1$ | None |
| 12 | ||||
| 13 | $k = 2$ | |||
| 14 | ||||
| 15 | $k = 3$ | |||
| 16 | ||||
| 17 | $1 \le k \le 10^9$ | |||
| 18 | ||||
| 19 | ||||
| 20 |