City United

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문제

In ICPCCamp there are nn cities which are conveniently labeled with 1,2,,n1, 2, \dots, n. There are also mm bidirectional roads: the ii-th road connects cities a_ia\_i and b_ib\_i.

Bobo chooses a non-empty subset of cities to form a union. For each two cities aa and bb in the union, there must exist a path from aa to bb passing through no cities outside the union. In other words, the union must be connected.

Bobo would like to know how many ways there are to choose such a subset, but he is afraid of large numbers. Therefore, he just wants to find this number modulo 22.

입력

The first line contains two integers nn and mm (1n501 \leq n \leq 50, 0mn(n1)20 \leq m \leq \frac{n(n - 1)}{2}). 

The ii-th of the following mm lines contains two integers a_ia\_i and b_ib\_i (1a_i,b_in1 \leq a\_i, b\_i \leq n, 0<a_ib_i130 < |a\_i - b\_i| \leq 13).

출력

Output an integer which denotes the number of possible subsets modulo 22.