bool M1;
#define look_memory cerr<<abs(&M2-&M1)/1024.0/1024<<" MB\n"
#define look_time cerr<<(clock()-Time)*1.0/CLOCKS_PER_SEC<<'\n'
#include <cstdio>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <cstring>
#include <array>
#include <algorithm>
#include <queue>
#include <vector>
#include <bitset>
#include <ctime>
#include <cstdlib>
#include <random>
#include <set>
#include <ctime>
#include <map>
#include <stack>
#include <unordered_map>
#include <assert.h>
#define i128 __int128
#define ll long long
#define uint unsigned
#define ull unsigned long long
#define ld long double
#define fo(a,b,c) for(ll a=b;a<=c;++a)
#define re(a,b,c) for(ll a=b;a>=c;--a)
#define pii pair<ll,ll>
#define pdd pair<db,db>
#define fi first
#define pb push_back
#define se second
#define ite set<pii> ::iterator
#define vite vector<ll> ::iterator
using namespace std;
const ll mod=998244353;
inline ll gi()
{
	ll x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if (ch == '-')
			f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x = (x<<1) + (x<<3) + (ch^48);
		ch = getchar();
	}
	return x * f;
}
ll _=1;
const ll inf=2e17+5,iinf=1e9;
const ll N=200005;
ll cnt;
struct IO
{
	ll tag,k,b,l,r;
	ll pv(ll x)
	{
		return k*x+b;
	}
}node[N*22];
ll lim=1000000;
void wk(ll rt,ll val)
{
	node[rt].b+=val;
	node[rt].tag+=val;
}
void pd(ll rt)
{
	if(node[rt].l)
	{
		wk(node[rt].l,node[rt].tag);
	}
	if(node[rt].r)
	{
		wk(node[rt].r,node[rt].tag);
	}
	node[rt].tag=0;
}
void ins(ll &rt,ll k,ll b,ll l=1,ll r=lim)
{
	if(!rt)
	{
		cnt++;
		node[cnt]={0,k,b,0,0};
		rt=cnt;
		return;
	}
	pd(rt);
	ll mid=(l+r)/2;
	if(node[rt].pv(mid)>k*mid+b)
	{
		swap(node[rt].b,b);
		swap(node[rt].k,k);
	}
	if(l==r) return;
	if(k>node[rt].k) ins(node[rt].l,k,b,l,mid);
	else ins(node[rt].r,k,b,mid+1,r);
}
ll qr(ll rt,ll x,ll l=1,ll r=lim)
{
	if(!rt) return inf;
	pd(rt);
	ll mid=(l+r)/2;
	ll res=node[rt].pv(x);
	if(l==r) return res;
	if(x<=mid) res=min(res,qr(node[rt].l,x,l,mid));
	else res=min(res,qr(node[rt].r,x,mid+1,r));
	return res;
}
ll n;
vector<ll> g[N];
ll a[N],root[N];
void mg(ll &x,ll y,ll l=1,ll r=lim)
{
	if(!x||!y)
	{
		x+=y;
		return;
	}
	ll mid=(l+r)/2;
	ins(x,node[y].k,node[y].b,l,r);
	if(l==r) return;
	pd(x);
	pd(y);
	mg(node[x].l,node[y].l,l,mid);
	mg(node[x].r,node[y].r,mid+1,r);
}
void dfs(ll u,ll fa)
{
	if(g[u].empty())
	{
		ins(root[u],a[u],0);
		return;
	}
	for(ll v:g[u])
	{
		if(v==fa) continue;
		dfs(v,u);
		if(!root[u]) root[u]=root[v];
		else
		{
			ll val1=qr(root[u],a[u]),val2=qr(root[v],a[u]);
			wk(root[u],val2);
			wk(root[v],val1);
			mg(root[u],root[v]);
		}
	}
}
void sol()
{
	n=gi();
	fo(i,2,n)
	{
		ll x=gi();
		g[x].pb(i);
	}
	fo(i,1,n) a[i]=gi();
	dfs(1,0);
	cout<<qr(root[1],a[1]);
}
bool M2;
int main()
{
	int Time=clock();
	look_memory;
//	_=gi();
	while(_--)
	{
		sol();
		printf("\n");
	}
	look_time;
	return 0;
}