Sets May Be Good

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문제

Consider an undirected graph GG with nn vertices. A subset of its vertices is good if the total number of edges between them (edges such that both their ends are in this subset) is even. How many good sets are there? Since this number may be large, output it modulo prime number 998,244,353998\\,244\\,353.

입력

The first line contains two integers nn and mm (1n10001 \le n \le 1000, 0mn(n1)20 \le m \le \frac{n(n-1)}{2}): the number of vertices and edges in the graph, respectively.

Each of the following mm lines contains two numbers uu and vv (1u,vn1 \le u, v \le n): the vertices connected by an edge.

The graph is guaranteed to contain no loops or multiple edges.

출력

Output the number of good sets modulo 998,244,353998\\,244\\,353.

힌트

In the second example, all sets are good. In the third example, the only non-good set is 1,2\\{1, 2\\}.