#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
const int N = 2e5 + 7;
#define int long long
int n;
int w[N] = {0};
int fa[N] = {0};
vector<int> G[N];
int sum[N] = {0};
int siz[N] = {0};
int ans = 0;

bool cmp(int a, int b) {
    return 1.0 * siz[a] / sum[a] > 1.0 * siz[b] / sum[b];
}

void dfs(int u = 1) {
    for (auto to: G[u]) {
        dfs(to);
        sum[u] += sum[to];
        siz[u] += siz[to];
    }
}

int cnt = 0;

void dfs1(int u = 1) {
    cnt++;
    ans += cnt * w[u];
    sort(G[u].begin(), G[u].end(), cmp);
    for (auto to: G[u]) {
        dfs1(to);
    }
}

void solve() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> w[i];
        sum[i] = w[i];
        siz[i] = 1;
    }
    for (int i = 2; i <= n; i++) {
        cin >> fa[i];
        G[fa[i]].push_back(i);
    }
    dfs();
    dfs1();
    cout << ans;
}

signed main() {
  //  freopen("D:\\Development_Software\\CLion\\CLionProjects\\Test\\in", "r", stdin);
    ios::sync_with_stdio(false);
    int T = 1;
    while (T--)solve();
}