#include<bits/stdc++.h>
using namespace std;
using ll=long long;
template<typename T>
ostream& operator << (ostream &out,const vector<T>&x){
	if(x.empty())return out<<"[]";
	out<<'['<<x[0];
	for(int len=x.size(),i=1;i<len;i++)out<<','<<x[i];
	return out<<']';
}
template<typename T>
vector<T> ary(const T *a,int l,int r){
	return vector<T>{a+l,a+1+r};
}
template<typename T>
void debug(T x){
	cerr<<x<<'\n';
}
template<typename T,typename ...S>
void debug(T x,S ...y){
	cerr<<x<<' ',debug(y...);
}
const int N=2e5+10,INF=1e9;
int n,a[N],b[N];
vector<int>to[N];
int fa[N],dep[N],son[N],siz[N],top[N];
int Min(int x,int y){
	return a[x]<a[y]?x:y;
}
int Max(int x,int y){
	return dep[x]>dep[y]?x:y;
}
void dfs1(int u){
	b[u]=to[u].size();
	dep[u]=dep[fa[u]]+1,siz[u]=1;
	for(int v:to[u]){
		dfs1(v);
		siz[u]+=siz[v];
		if(siz[v]>siz[son[u]])son[u]=v;
	}
}
int dft,dfn[N],pos[N];
void dfs2(int u,int t){
	top[u]=t,pos[dfn[u]=++dft]=u;
	if(son[u])dfs2(son[u],t);
	for(int v:to[u])if(v^son[u])dfs2(v,v);
}
int t[N<<2],v[N<<2];
void pushup(int rt){
	t[rt]=Min(t[rt<<1],t[rt<<1|1]);
	v[rt]=Max(v[rt<<1],v[rt<<1|1]);
}
bool chk(int u){
	return b[u]>(u!=1);
}
void build(int l=1,int r=n,int rt=1){
	if(l==r){
		t[rt]=chk(pos[l])?pos[l]:0;
		v[rt]=l>1?0:1;
		return;
	}
	int mid=(l+r)>>1;
	build(l,mid,rt<<1);
	build(mid+1,r,rt<<1|1);
	pushup(rt);
}
void erase(int x,int l=1,int r=n,int rt=1){
	if(l==r){
		t[rt]=0;return;
	}
	int mid=(l+r)>>1;
	if(x<=mid)erase(x,l,mid,rt<<1);
	else erase(x,mid+1,r,rt<<1|1);
	pushup(rt);
}
void insert(int L,int R,int l=1,int r=n,int rt=1){
	if(l==r){
		v[rt]=pos[l];return;
	}
	int mid=(l+r)>>1;
	if(L<=mid)insert(L,R,l,mid,rt<<1);
	if(mid<R)insert(L,R,mid+1,r,rt<<1|1);
	pushup(rt);
}
int query(int L,int R,int l=1,int r=n,int rt=1){
	if(L<=l&&r<=R)return t[rt];
	int mid=(l+r)>>1,s=0;
	if(L<=mid)s=Min(s,query(L,R,l,mid,rt<<1));
	if(mid<R)s=Min(s,query(L,R,mid+1,r,rt<<1|1));
	return s;
}
int find(int L,int R,int l=1,int r=n,int rt=1){
	if(L<=l&&r<=R)return v[rt];
	int mid=(l+r)>>1,s=0;
	if(L<=mid)s=Max(s,find(L,R,l,mid,rt<<1));
	if(mid<R)s=Max(s,find(L,R,mid+1,r,rt<<1|1));
	return s;
}
ll ans;
void solve(int u){
	int p=0,q=0;
	for(int x=u;x;x=fa[top[x]]){
		q=Max(q,find(dfn[top[x]],dfn[x]));
	}
	for(int x=u;x;x=fa[top[x]]){
		if(top[x]^top[q]){
			p=Min(p,query(dfn[top[x]],dfn[x]));
		}else{
			p=Min(p,query(dfn[q],dfn[x]));break;
		}
	}
	// debug(u,p,q);
	ans+=1ll*a[u]*a[p];
	for(int x=u;p^x;x=fa[top[x]]){
		if(top[x]^top[p]){
			insert(dfn[top[x]],dfn[x]);
		}else{
			insert(dfn[p]+1,dfn[x]);break;
		}
	}
	if(b[p]--,!chk(p)){
		// debug("ers",p);
		erase(dfn[p]);
	}
}
int main(){
	scanf("%d",&n);
	for(int i=2;i<=n;i++){
		scanf("%d",&fa[i]),to[fa[i]].push_back(i);
		// debug(fa[i],i);
	}
	for(int i=1;i<=n;i++)scanf("%d",&a[i]);
	a[0]=INF;
	dfs1(1),dfs2(1,1);
	vector<int>t;
	for(int i=2;i<=n;i++){
		if(!b[i])t.push_back(i);
	}
	sort(t.begin(),t.end(),[](int x,int y){
		return a[x]>a[y];
	});
	build();
	for(int x:t)solve(x);
	cout<<ans<<endl;
	return 0;
}