B'You are given a weighted undirected tree on n vertices and a list of q updates. Each update changes the weight of one edge. The task is to output the diameter of the tree after each update. (The distance between two vertices is the sum of the weights on the unique simple path that connects them. The diameter is the largest of all those distances.) The first line contains three space-separated integers n , q and w ( 2 <= q n <= q 100,000, 1 <= q q <= q 100,000 , 1 <= q w <= q 20,000,000,000,000 ) xe2 x80 x93 the number of vertices in the tree, the number of updates and the limit on the weights of edges. The vertices are numbered 1 through n . Next, n-1 lines describing the initial tree follow. The i -th of these lines contains three space-separated integers a_i , b_i , c_i ( 1 <= q a_i, b_i <= q n , 0 <= q c_i < w ) meaning that initially, there is an edge between vertices a_i and b_i with weight c_i . It is guaranteed that these n-1 lines describe a tree. Finally, q lines describing queries follow. The j -th of these lines contains two space-separated integers d_j , e_j ( 0 <= q d_j < n - 1, 0 <= q e_j < w ). These two integers are then transformed according to the following scheme: Output q lines. For each i , line i should contain the diameter of the tree after the i -th update. Subtask 1 (11 points): n,q <= q 100 and w <= q 10,000 Subtask 2 (13 points): n,q <= q 5,000 and w <= q 10,000 Subtask 3 (7 points): w <= q 10,000 and the edges of the tree are exactly all valid edges of the form {1, i } (Hence, the tree is a star centered at vertex 1.) Subtask 4 (18 points): w <= q 10,000 , and the edges of the tree are exactly all valid edges of the forms {i, 2i } and {i, 2i+1 } (Hence, if we were to root the tree at vertex 1, it would be a balanced binary t'...