#include<bits/stdc++.h>
const int N = 300005;
const int mod = 1e9 + 7;
using ll = long long;
using pr = std::pair<int, int>;
using std::cin;
using std::cout;
struct func {
	ll k, a;
	ll operator () (ll x) const {
		return x * k + a;
	}
};

int cnt;
const int M = N * 40;
ll add[M];
func f[M];
int ls[M], rs[M];

void put(int x, ll v) {
	if(!x) return ;
	f[x].a += v;
	add[x] += v;
}
void down(int x) {
	put(ls[x], add[x]);
	put(rs[x], add[x]);
	add[x] = 0;
}
void ins(int & rt, func x, int l = 1, int r = 1e6) {
	if(!rt) return void(f[rt = ++ cnt] = x);
	int mid = (l + r) >> 1;
	if(x(mid) < f[rt](mid)) {
		std::swap(x, f[rt]);
	}
	down(rt);
	if(l == r) return ;
	if(x(l) < f[rt](l)) ins(ls[rt], x, l, mid);
	if(x(r) < f[rt](r)) ins(rs[rt], x, mid + 1, r);
}
ll qry(int rt, int p, int l = 1, int r = 1e6) {
	if(!rt) return 1e18;
	down(rt);
	int mid = (l + r) >> 1;
	ll ans = f[rt](p);
	if(p <= mid) {
		ans = std::min(ans, qry(ls[rt], p, l, mid));
	} else {
		ans = std::min(ans, qry(rs[rt], p, mid + 1, r));
	}
	return ans;
}
int merge(int x, int y, int l = 1, int r = 1e6) {
	if(!x || !y) return x | y;
	down(x); down(y);
	int mid = (l + r) >> 1;
	ls[x] = merge(ls[x], ls[y], l, mid);
	rs[x] = merge(rs[x], rs[y], mid + 1, r);
	ins(x, f[y], l, r);
	return x;
}

int n, m;
std::vector<int> go[N];
int c[N];
int root[N];
void dfs0(int x) {
	if(go[x].empty()) {
		ins(root[x], {c[x], 0});
	} else {
		std::vector<int> roots;
		std::vector<ll> val;
		ll sum = 0;
		for(int w : go[x]) {
			dfs0(w);
			roots.push_back(root[w]);
			val.push_back(qry(root[w], c[x]));
			sum += val.back();
		}
		for(int i = 0;i < (int) roots.size();++i) {
			put(roots[i], sum - val[i]);
			root[x] = merge(root[x], roots[i]);
		}
	}
}
int main() {
	std::ios::sync_with_stdio(false), cin.tie(0);
	cin >> n;
	for(int i = 2, f;i <= n;++i) {
		cin >> f, go[f].push_back(i);
	}
	for(int i = 1;i <= n;++i) cin >> c[i];
	dfs0(1);
	cout << qry(root[1], c[1]) << '\n';
}