The first line contains a positive integer, T, representing the number of test cases, where 1≤T≤20.
Next, for each test case, the following format is repeated:
The first line contains a positive integer, n, where 1≤n≤10^5. The next n lines contain two integers, Ai and Bi, representing the two attributes of the ith stone. The values of Ai and Bi satisfy 0≤Ai,Bi≤10^9.
2
3
0 2
1 2
3 3
3
1 0
2 3
0 4
1
-1