Problem Statement
You are given a simple connected undirected graph $G$ with $N$ vertices and $M$ edges. The vertices are numbered $1$ to $N$, and the $i$-th edge connects vertices $A_i$ and $B_i$.
Find the number of ways to paint each edge of $G$ in color $1$, $2$, or $3$ so that the following condition is satisfied, modulo $998244353$.
- There is a simple path in
$G$that contains an edge in color$1$, an edge in color$2$, and an edge in color$3$.
What is a simple path? A simple path is a pair of a sequence of vertices $(v_1, \ldots, v_{k+1})$ and a sequence of edges $(e_1, \ldots, e_k)$ that satisfies the following: $i\neq j \implies v_i\neq v_j$; edge $e_i$ connects vertices $v_i$ and $v_{i+1}$.
Constraints
$3 \leq N\leq 2\times 10^5$$3 \leq M\leq 2\times 10^5$$1 \leq A_i, B_i \leq N$- The given graph is simple and connected.
Input
The input is given from Standard Input in the following format:
N M
A_1 B_1
\vdots
A_M B_M
Output
Print the number of ways to paint each edge of $G$ in color $1$, $2$, or $3$ so that the condition in question is satisfied, modulo $998244353$.
样例
3 3
1 2
1 3
3 2
0
4 6
1 2
1 3
1 4
2 3
2 4
3 4
534
6 5
1 3
4 3
5 4
4 2
1 6
144
6 7
1 2
2 3
3 1
4 5
5 6
6 4
1 6
1794
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