#include<bits/stdc++.h>
using namespace std;
int n,w[500005],d[500005];
vector<int>g[500005];
vector<int>ans;
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		int a;scanf("%d",&a);
		if(a==0)continue;
		g[a].push_back(i);d[i]++;
	}
	for(int i=1;i<=n;i++)scanf("%d",&w[i]);
	priority_queue<pair<int,int>>q;
	for(int i=1;i<=n;i++)if(!d[i])q.push(make_pair(-w[i],i));
	while(!q.empty()){
		int x=q.top().second;q.pop();
		ans.push_back(x);
		for(int y:g[x]){
			if(--d[y]==0)q.push(make_pair(-w[y],y));
		}
	}
	if(ans.size()==n){
		long long ret=0;
		for(int i=0;i<n;i++)ret+=1ll*w[ans[i]]*(i+1);
		printf("%d\n",ret);
	}else printf("-1\n");
}