F. Greetingstime limit per test5 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputThere 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, \dots, a_n, b_1, b_2, \dots, 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.InputThe first line of the input contains a single integer t (1 \le t \le 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 \le n \le 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 \leq a_i < b_i \leq 10^9) — the starting and ending positions of each person.For each test case, all of the 2n numbers a_1, a_2, \dots, a_n, b_1, b_2, \dots, b_n are distinct.The sum of n over all test cases does not exceed 2 \cdot 10^5.OutputFor each test case, output a single integer denoting the number of greetings that will happen.ExampleInput
522 31 462 63 94 51 87 10-2 1004-10 10-5 5-12 12-13 135-4 9-2 53 46 78 1041 23 45 67 8Output
1
9
6
4
0
NoteIn the first test case, the two people will meet at point 3 and greet each other.
522 31 462 63 94 51 87 10-2 1004-10 10-5 5-12 12-13 135-4 9-2 53 46 78 1041 23 45 67 8
1 9 6 4 0 
['data structures', 'divide and conquer', 'sortings', '*1500']