102847: [AtCoder]ABC284 Ex - Count Unlabeled Graphs

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

Score : $600$ points

Problem Statement

You are to generate a graph by the following procedure.

  • Choose a simple undirected graph with $N$ unlabeled vertices.
  • Write a positive integer at most $K$ in each vertex in the graph. Here, there must not be a positive integer at most $K$ that is not written in any vertex.

Find the number of possible graphs that can be obtained, modulo $P$. ($P$ is a prime.)

Two graphs are considered the same if and only if one can label the vertices in each graph as $v_1, v_2, \dots, v_N$ to satisfy the following conditions.

  • For every $i$ such that $1 \leq i \leq N$, the numbers written in vertex $v_i$ in the two graphs are the same.
  • For every $i$ and $j$ such that $1 \leq i \lt j \leq N$, there is an edge between $v_i$ and $v_j$ in one of the graphs if and only if there is an edge between $v_i$ and $v_j$ in the other graph.

Constraints

  • $1 \leq K \leq N \leq 30$
  • $10^8 \leq P \leq 10^9$
  • $P$ is a prime.
  • All values in the input are integers.

Input

The input is given from Standard Input in the following format:

$N$ $K$ $P$

Output

Print the answer.


Sample Input 1

3 1 998244353

Sample Output 1

4

The following four graphs satisfy the condition.

image


Sample Input 2

3 2 998244353

Sample Output 2

12

The following $12$ graphs satisfy the condition.

image2


Sample Input 3

5 5 998244353

Sample Output 3

1024

Sample Input 4

30 15 202300013

Sample Output 4

62712469

Input

题意翻译

给定整数 $n$,$k$,和质数 $P$。 你需要在一个 $n$ 个节点的无标号无向图上给每一个节点标上一个 $1$ 到 $k$ 的数,且每一个数都要用到,求出标号后本质不同的图的数量对 $P$ 取模。

Output

分数:$600$分

问题描述

你需要通过以下步骤生成一个图。

  • 选择一个具有$N$个无标签顶点的简单无向图。
  • 在图中的每个顶点上写下不超过$K$的正整数。这里,不能有任何正整数不超过$K$而没有写在任何顶点上。

找出可以得到的可能图的数量,对$P$取模。($P$是一个质数。)

只有当以下条件都满足时,才认为两个图是相同的。

  • 对于每个$1 \leq i \leq N$,在两个图中顶点$v_i$上写下的数字是相同的。
  • 对于每个$1 \leq i \lt j \leq N$,如果在一个图中存在边连接顶点$v_i$和$v_j$,则另一个图中也必须存在边连接顶点$v_i$和$v_j$,反之亦然。

约束条件

  • $1 \leq K \leq N \leq 30$
  • $10^8 \leq P \leq 10^9$
  • $P$是质数。
  • 输入中的所有值都是整数。

输入

输入通过标准输入给出,如下所示:

$N$ $K$ $P$

输出

打印答案。


样例输入1

3 1 998244353

样例输出1

4

以下四个图满足条件。

image


样例输入2

3 2 998244353

样例输出2

12

以下12个图满足条件。

image2


样例输入3

5 5 998244353

样例输出3

1024

样例输入4

30 15 202300013

样例输出4

62712469

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