grf

题号：NC17404
时间限制：C/C++/Rust/Pascal 4秒，其他语言8秒
空间限制：C/C++/Rust/Pascal 512 M，其他语言1024 M
64bit IO Format: %lld

题目描述

Kanade has a undirected graph of n nodes and m edges without multiple edges and self loops.And let V denote the set of its vertex and E denote the set of its edges

For every subset S of E , let k(S) denote the number of connected component of graph <V,S>

And now you need to calculate $\sum_{S\subseteq E} k(S)^{k(S)-1}$

You only need to output the answer module 998244353

输入描述:

The first line has two integers n,m

Then there are n lines, each line has two integers x,y denote the edge (x,y)

输出描述:

Output the answer module 998244353

示例1

输入

复制

输出

复制

备注:

1 ≤ n≤ 19
0≤ m≤ (n-1)n/2
1≤ x,y ≤ n