B'You are given a directed acyclic graph with n vertices and m edges. For all edges a to b in the graph, a < b holds. You need to find the number of pairs of vertices x , y , such that x > y and after adding the edge x to y to the graph, it has a Hamiltonian path. The first line of input contains one integer t ( 1 <= q t <= q 5 ): the number of test cases. The next lines contains the descriptions of the test cases. In the first line you are given two integers n and m ( 1 <= q n <= q 150 ,000 , 0 <= q m <= q min(150 ,000, frac{n(n-1)}{2}) ): the number of vertices and edges in the graph. Each of the next m lines contains two integers a , b ( 1 <= q a < b <= q n ), specifying an edge a to b in the graph. No edge a to b appears more than once. For each test case, print one integer: the number of pairs of vertices x , y , x > y , such that after adding the edge x to y to the graph, it has a Hamiltonian path. In the first example, any edge x to y such that x > y is valid, because there already is a path 1 to 2 to 3 . In the second example only the edge 4 to 1 is valid. There is a path 3 to 4 to 1 to 2 if this edge is added. In the third example you can add edges 2 to 1 , 3 to 1 , 4 to 1 , 4 to 2 . '...