#include<bits/stdc++.h>
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,avx,avx2,popcnt,tune=native")
#define ll long long
#define pb push_back
#define lb(x) x&-x
using namespace std;
const int maxn=2e5+10,maxc=1e6+10,C=1e6;
int n,fa[maxn],c[maxn],tim,L[maxn],R[maxn],dfh[maxn],cnt,root[maxn];
ll f[maxn],tag[maxn],sm[maxn];
vector<int> e[maxn];
inline int read()
{
	int x=0;
	char c=getchar();
	while(!isdigit(c)) c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return x;
}
inline void write(register int x)
{
    if(x>9) write(x/10);
    putchar(x%10+'0');
}
inline void modify(register int x,register ll val)
{
	for(;x<=n;x+=lb(x)) f[x]+=val;
}
inline ll query(register int x)
{
	ll res=0;
	for(;x;x-=lb(x)) res+=f[x];
	return res;
}
struct line
{
	int k;
	ll b;
	line(){}
	line(register int K,register ll B){k=K,b=B;}
	ll y(register int x){return 1ll*k*x+b;}
};
struct node
{
	int l,r;
	line X;
}t[maxc<<5];
inline void modify2(int l,int r,int id,line X)
{
	int mid=(l+r)>>1;
	if(t[id].X.y(mid)>X.y(mid)) swap(t[id].X,X);
	if(t[id].X.y(l)>X.y(l))
	{
		if(t[id].l) modify2(l,mid,t[id].l,X);
		else cnt++,t[cnt].X=X,t[id].l=cnt;
	}
	else if(t[id].X.y(r)>X.y(r))
	{
		if(t[id].r) modify2(mid+1,r,t[id].r,X);
		else cnt++,t[cnt].X=X,t[id].r=cnt;
	}
}
inline ll query2(int l,int r,int id,int loc)
{
	if(!id) return 1e18;
	if(l==r) return t[id].X.y(loc);
	int mid=(l+r)>>1;
	if(loc<=mid) return min(t[id].X.y(loc),query2(l,mid,t[id].l,loc));
	return min(t[id].X.y(loc),query2(mid+1,r,t[id].r,loc));
}
inline void dfs(int now)
{
	int son=0;
	ll tot=0;
	L[now]=tim+1;
	for(int i:e[now])
	{
		dfs(i),sm[i]=query2(1,C,root[i],c[now])+tag[i],tot+=sm[i];
		if(son==0||R[i]-L[i]>R[son]-L[son]) son=i;
	}
	if(!son)
	{
		tim++,dfh[tim]=now,R[now]=tim,cnt++,root[now]=cnt,t[cnt].X=line(c[now],0);
		return;
	}
	root[now]=root[son],tag[now]=tag[son]+tot-sm[son],modify(L[son],tot-sm[son]),modify(R[son]+1,sm[son]-tot);
	for(int i:e[now])
	{
		if(i!=son)
		{
			modify(L[i],tot-sm[i]),modify(R[i]+1,sm[i]-tot);
			for(register int j=L[i];j<=R[i];j++) modify2(1,C,root[now],line(c[dfh[j]],query(j)-tag[now]));
		}
	}
	R[now]=tim;
}
int main()
{
	scanf("%d",&n);
	for(register int i=2;i<=n;i++) scanf("%d",&fa[i]),e[fa[i]].pb(i);
	for(register int i=1;i<=n;i++) scanf("%d",&c[i]);
	dfs(1),printf("%lld\n",query2(1,C,root[1],c[1])+tag[1]);
	return 0;
}