Description: You are given a rooted tree, consisting of $$$n$$$ vertices. The vertices in the tree are numbered from $$$1$$$ to $$$n$$$, and the root is the vertex $$$1$$$. The value $$$a_i$$$ is written at the $$$i$$$-th vertex. You can perform the following operation any number of times (possibly zero): choose a vertex $$$v$$$ which has at least one child; increase $$$a_v$$$ by $$$1$$$; and decrease $$$a_u$$$ by $$$1$$$ for all vertices $$$u$$$ that are in the subtree of $$$v$$$ (except $$$v$$$ itself). However, after each operation, the values on all vertices should be non-negative. Your task is to calculate the maximum possible value written at the root using the aforementioned operation. Input Format: The first line contains a single integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases. The first line of each test case contains a single integer $$$n$$$ ($$$2 \le n \le 2 \cdot 10^5$$$) — the number of vertices in the tree. The second line contains $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$ ($$$0 \le a_i \le 10^9$$$) — the initial values written at vertices. The third line contains $$$n-1$$$ integers $$$p_2, p_3, \dots, p_n$$$ ($$$1 \le p_i \le n$$$), where $$$p_i$$$ is the parent of the $$$i$$$-th vertex in the tree. Vertex $$$1$$$ is the root. Additional constraint on the input: the sum of $$$n$$$ over all test cases doesn't exceed $$$2 \cdot 10^5$$$. Output Format: For each test case, print a single integer — the maximum possible value written at the root using the aforementioned operation. Note: In the first test case, the following sequence of operations is possible: - perform the operation on $$$v=3$$$, then the values on the vertices will be $$$[0, 1, 1, 1]$$$; - perform the operation on $$$v=1$$$, then the values on the vertices will be $$$[1, 0, 0, 0]$$$.