P2568 [CF1613F] Tree Coloring
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题目描述

You are given a rooted tree consisting of $n$ vertices numbered from $1$ to $n$. The root of the tree is the vertex $1$.

You have to color all vertices of the tree into $n$ colors (also numbered from $1$ to $n$) so that there is exactly one vertex for each color. Let $c_i$ be the color of vertex $i$, and $p_i$ be the parent of vertex $i$ in the rooted tree. The coloring is considered beautiful if there is no vertex $k$ ($k > 1$) such that $c_k = c_{p_k} - 1$, i. e. no vertex such that its color is less than the color of its parent by exactly $1$.

Calculate the number of beautiful colorings, and print it modulo $998244353$.

Input

The first line contains one integer $n$ ($2 \le n \le 250000$) — the number of vertices in the tree.

Then $n-1$ lines follow, the $i$-th line contains two integers $x_i$ and $y_i$ ($1 \le x_i, y_i \le n$; $x_i \ne y_i$) denoting an edge between the vertex $x_i$ and the vertex $y_i$. These edges form a tree.

Output

Print one integer — the number of beautiful colorings, taken modulo $998244353$.

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
5 1 2 3 2 4 2 2 5
样例输出
42