Shuffle

Description:

Input:

The first line contains a single integer $$$t$$$ ($$$1 \le t \le 100$$$) — the number of test cases. Then the description of $$$t$$$ testcases follow.

The first line of each test case contains three integers $$$n$$$, $$$x$$$ and $$$m$$$ ($$$1 \le n \le 10^9$$$; $$$1 \le m \le 100$$$; $$$1 \le x \le n$$$).

Each of next $$$m$$$ lines contains the descriptions of the operations; the $$$i$$$-th line contains two integers $$$l_i$$$ and $$$r_i$$$ ($$$1 \le l_i \le r_i \le n$$$).

Output:

For each test case print one integer — the number of indices $$$k$$$ such that it is possible to choose the operations so that $$$a_k = 1$$$ in the end.

Sample Input:

3
6 4 3
1 6
2 3
5 5
4 1 2
2 4
1 2
3 3 2
2 3
1 2

Sample Output:

6
2
3

Note:

In the first test case, it is possible to achieve $$$a_k = 1$$$ for every $$$k$$$. To do so, you may use the following operations:

1. swap $$$a_k$$$ and $$$a_4$$$;
2. swap $$$a_2$$$ and $$$a_2$$$;
3. swap $$$a_5$$$ and $$$a_5$$$.

In the second test case, only $$$k = 1$$$ and $$$k = 2$$$ are possible answers. To achieve $$$a_1 = 1$$$, you have to swap $$$a_1$$$ and $$$a_1$$$ during the second operation. To achieve $$$a_2 = 1$$$, you have to swap $$$a_1$$$ and $$$a_2$$$ during the second operation.