Description:
Alex is solving a problem. He has $$$n$$$ constraints on what the integer $$$k$$$ can be. There are three types of constraints:
1. $$$k$$$ must be greater than or equal to some integer $$$x$$$;
2. $$$k$$$ must be less than or equal to some integer $$$x$$$;
3. $$$k$$$ must be not equal to some integer $$$x$$$.
Help Alex find the number of integers $$$k$$$ that satisfy all $$$n$$$ constraints. It is guaranteed that the answer is finite (there exists at least one constraint of type $$$1$$$ and at least one constraint of type $$$2$$$). Also, it is guaranteed that no two constraints are the exact same.
Input Format:
Each test consists of multiple test cases. The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 500$$$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains a single integer $$$n$$$ ($$$2 \leq n \leq 100$$$) — the number of constraints.
The following $$$n$$$ lines describe the constraints. Each line contains two integers $$$a$$$ and $$$x$$$ ($$$a \in \{1,2,3\}, \, 1 \leq x \leq 10^9$$$). $$$a$$$ denotes the type of constraint. If $$$a=1$$$, $$$k$$$ must be greater than or equal to $$$x$$$. If $$$a=2$$$, $$$k$$$ must be less than or equal to $$$x$$$. If $$$a=3$$$, $$$k$$$ must be not equal to $$$x$$$.
It is guaranteed that there is a finite amount of integers satisfying all $$$n$$$ constraints (there exists at least one constraint of type $$$1$$$ and at least one constraint of type $$$2$$$). It is also guaranteed that no two constraints are the exact same (in other words, all pairs $$$(a, x)$$$ are distinct).
Output Format:
For each test case, output a single integer — the number of integers $$$k$$$ that satisfy all $$$n$$$ constraints.
Note:
In the first test case, $$$k \geq 3$$$ and $$$k \leq 10$$$. Furthermore, $$$k \neq 1$$$ and $$$k \neq 5$$$. The possible integers $$$k$$$ that satisfy the constraints are $$$3,4,6,7,8,9,10$$$. So the answer is $$$7$$$.
In the second test case, $$$k \ge 5$$$ and $$$k \le 4$$$, which is impossible. So the answer is $$$0$$$.