#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>
#include<iterator>

#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define rep(i,n) for(int i=0; i<n; i++)

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, char> plc;

#define MAX_N 100100
#define MAX_LOG_N 30
int N, root;
ll ans;
vector<int> g[MAX_N];
int depth[MAX_N];
int par[MAX_N][MAX_LOG_N];
int U[MAX_N * 2];
int sum[100100];

void bfs() {
	queue<int> q;

	sum[0] = U[0];

	q.push(0);
	while (!q.empty()) {
		int i = q.front(); q.pop();

		for (int j : g[i])if (sum[j] == 0) {
			sum[j] = sum[i] + U[j];
			q.push(j);
		}
	}
}

void dfs(int v, int p, int d)
{
	par[v][0] = p;
	depth[v] = d;
	for (int i = 0; i < g[v].size(); i++)
	{
		if (g[v][i] == p)continue;
		dfs(g[v][i], v, d + 1);
	}
}

void fill_table()
{
	for (int i = 0; i < 30-1; i++)
	{
		for (int j = 0; j < N; j++)
		{
			if (par[j][i] == -1)par[j][i + 1] = -1;
			else par[j][i + 1] = par[par[j][i]][i];
		}
	}
}

int lca(int u, int v)
{
	int tmp_u = u, tmp_v = v;
	if (depth[u] > depth[v])swap(u, v);
	for (int i = 19; i >= 0; i--)
	{
		if (((depth[v] - depth[u]) >> i) & 1) {
			v = par[v][i];
		}
	}
	if (u == v)return u;
	for (int i = 19; i >= 0; i--)
	{
		if (par[u][i] != par[v][i])
		{
			u = par[u][i];
			v = par[v][i];
		}
	}
	return par[u][0];
}

int dist(int u, int v) {
	return depth[u] + depth[v] - 2 * depth[lca(u, v)];
}

int main()
{
	int q;
	cin >> N;

	rep(i, N-1) {
		int x, y;
		cin >> x >> y;
		
		g[x].push_back(y);
		g[y].push_back(x);
	}
	root = 0;
	dfs(root, -1, 0);
	fill_table();

	rep(i, N)cin >> U[i];
	
	bfs();

	cin >> q;
	rep(i, q) {
		int u, v,c;
		cin >> u >> v >> c;
		int p = lca(u, v);
		ans += (sum[u] + sum[v] - sum[p] * 2 + U[p]) * c;
	}
	cout << ans << endl;
	return 0;
}