#include <iostream>
#include <climits>
#include <vector>

using namespace std;

int res = INT_MIN;
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};

TreeNode* createTree(vector<int> valList, vector<int> fatherList) {
    vector<TreeNode*> nodeList;
    for (auto val : valList) {
        nodeList.push_back(new TreeNode(val));
    }
    for (int i = 1; i < fatherList.size(); i ++) {
        if (nodeList[fatherList[i] - 1]->left == nullptr) {
            nodeList[fatherList[i] - 1]->left = nodeList[i];
        } else {
            nodeList[fatherList[i] - 1]->right = nodeList[i];
        }
    }
    return nodeList[0];
}

int dfs(TreeNode* root)
{
    if (!root) return 0;

    auto left = max(0, dfs(root->left)), right = max(0, dfs(root->right));

    res = max(res, root->val + left + right);

    return root->val + max(left, right);
}

int main() {
    int n;
    cin >> n;
    vector<int> valList(n, 0);
    vector<int> fatherList(n, 0);
    for (int i = 0; i < n; i ++) {
        cin >> valList[i];
    }
    for (int i = 0; i < n; i ++) {
        cin >> fatherList[i];
    }
    auto root = createTree(valList, fatherList);
    dfs(root);
    cout << res << endl;

    return 0;
}