B"You are given a tree with n vertices, rooted at vertex 1 . The i -th vertex has an integer a_i written on it. Let L be the set of all direct children ^{ text{ xe2 x88 x97}} of v . A tree is called wonderful, if for all vertices v where L is not empty, a_v <= sum_{u in L}{a_u}. In one operation, you choose any vertex v and increase a_v by 1 . Find the minimum number of operations needed to make the given tree wonderful! ^{ text{ xe2 x88 x97}} Vertex u is called a direct child of vertex v if: Each test contains multiple test cases. The first line of input contains a single integer t ( 1 <= t <= 1000 ) -- the number of test cases. The description of the test cases follows. The first line of each test case contains a single integer n ( 2 <= n <= 5000 ) -- the number of vertices in the tree. The second line of each test case contains n integers a_1, a_2, ldots, a_n ( 0 <= a_i <= 10^9 ) -- the values initially written on the vertices. The third line of each test case contains n - 1 integers p_2, p_3 , ldots, p_n ( 1 <= p_i < i ), indicating that there is an edge from vertex p_i to vertex i . It is guaranteed that the given edges form a tree. It is guaranteed that the sum of n over all test cases does not exceed 5000 . For each test case, output a single integer -- the minimum number of operations needed to make the tree wonderful. The tree in the first test case: You can apply the operation once on vertex 5 and twice on vertex 2 to get a wonderful tree. In the second test case, you can apply the operation twice on vertex 2 to get a wonderful tree. In the third and fourth test cases, the tree is already wonderful, so you don't need to apply any operations. "...