#include <bits/stdc++.h>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a - 1; i >= 0; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a - 1; i >= b; --i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define popcount __builtin_popcount
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;


template <class T>
inline bool chmin(T &a, T b)
{
	if (a > b)
	{
		a = b;
		return true;
	}
	return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
	if (a < b)
	{
		a = b;
		return true;
	}
	return false;
}

ll gcd(ll n, ll m)
{
	ll tmp;
	while (m != 0)
	{
		tmp = n % m;
		n = m;
		m = tmp;
	}
	return n;
}

ll lcm(ll n, ll m)
{
	return abs(n) / gcd(n, m) * abs(m); //gl=xy
}

using namespace std;

vector<vector<int>>g;
vector<ll>sum,a,b;

void dfs(int v,int par=-1){
	for(auto x:g[v]){
		if(x!=par){
			sum[v]+=b[x];
			sum[x]+=b[v];
			dfs(x,v);
		}
	}
}

void solve(){
	int n;
	cin>>n;
	a.resize(n),b.resize(n);
	rep(i,n)cin>>a[i];
	rep(i,n)cin>>b[i];
	g.resize(n);
	rep(i,n-1){
		int u,v;
		cin>>u>>v;
		u--;v--;
		g[u].pb(v);
		g[v].pb(u);
	}
	sum.resize(n);
	dfs(0);
	ll ans=0;
	vector<ll>cnt(n);
	rep(i,n)cnt[i]=g[i].size();
	rep(i,n){
		ll add=a[i]-sum[i]-b[i]*cnt[i];
		//cout<<add<<"\n";
		if(add>0){
			ans+=a[i];
			for(auto x:g[i]){
				--cnt[x];
				sum[x]-=b[i];
			}
			b[i]=0;
		}
	}
	rep(i,n)ans+=b[i]*cnt[i];
	cout<<ans<<"\n";
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}