**Problem Description**

**Input**

The first line of data is the number of cases T.

For each case data :

The first line is two integers n and m, which represent the number of ninja and the number of relationship.

Next m lines, two integers u, v. This means that ninja u and ninja v know each other.

We ensure that the u and v is different and every relationship appears exactly once.

T <= 10

1<= n <= 20, 0<=m<=min(n*(n-1)/2,20)

1 <= u, v <= n

**Output**

Each set of data line, directly output the answer.

**Sample Input**

1 2 1 1 2

**Sample Output**

2

**Source**

2019绍兴市计算机技能竞赛