B'There are n people on the number line; the i -th person is at point a_i and wants to go to point b_i . For each person, a_i < b_i , and the starting and ending points of all people are distinct. (That is, all of the 2n numbers a_1, a_2, ... , a_n, b_1, b_2, ... , b_n are distinct.) All the people will start moving simultaneously at a speed of 1 unit per second until they reach their final point b_i . When two people meet at the same point, they will greet each other once. How many greetings will there be? Note that a person can still greet other people even if they have reached their final point. The first line of the input contains a single integer t ( 1 <= t <= 10^4 ) -- the number of test cases. The description of test cases follows. The first line of each test case contains a single integer n ( 1 <= n <= 2 cdot 10^5 ) -- the number of people. Then n lines follow, the i -th of which contains two integers a_i and b_i ( -10^9 <= q a_i < b_i <= q 10^9 ) -- the starting and ending positions of each person. For each test case, all of the 2n numbers a_1, a_2, ... , a_n, b_1, b_2, ... , b_n are distinct. The sum of n over all test cases does not exceed 2 cdot 10^5 . For each test case, output a single integer denoting the number of greetings that will happen. In the first test case, the two people will meet at point 3 and greet each other. '...