#include <iostream>
#include <cstdio>
using namespace std;
struct Tree{int l,r;}p[5001];
int dp[5001][2];
void Scanf(int &x){
    x=0;char s=getchar();
    while (s<'0'||s>'9')s=getchar();
    while (s>='0'&&s<='9') x=x*10+s-'0',s=getchar();
}
void Tree_DP(int id){
    if(!p[id].l)return;
    for(int i=p[id].l;i;i=p[i].r){
        Tree_DP(i);dp[id][0]+=max(dp[i][0],dp[i][1]),
        dp[id][1]+=dp[i][0];
    }
}
int main(){
    int n,father,i;
    scanf("%d",&n);
    for(i=1;i<=n;++i)scanf("%d",&dp[i][1]);
    for(i=2;i<=n;++i){
        scanf("%d",&father);
        if(!p[father].l)p[father].l=i;
        else{
            for(father=p[father].l;p[father].r;father=p[father].r);
            p[father].r=i;
        }
    }Tree_DP(1),printf("%d",max(dp[1][0],dp[1][1]));
    return 0;
}