#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)

typedef long long ll;
int N;
vector<int> E[101010];
int U[101010];
//-----------------------------------------------------------------
int sum[101010];
void bfs() {
	queue<int> que;

	sum[0] = U[0];

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

		for (int j : E[i]) if (sum[j] == 0) {
			sum[j] = sum[i] + U[j];
			que.push(j);
		}
	}
}
//-----------------------------------------------------------------
class LCA
{
public:
	int NV;
	int logNV;
	vector<int> D;
	vector<long long> L;
	vector<vector<int> > P;

	LCA(int N)
	{
		NV = N;
		logNV = 0;
		while (NV > (1LL << logNV)) logNV++;
		D = vector<int>(NV);
		L = vector<long long>(NV);
		P = vector<vector<int> >(logNV, vector<int>(NV));
	}

	void init()
	{
		dfs(0, -1, 0, 0);
		build();
	}

	void dfs(int v, int par, int d, long long l)
	{
		D[v] = d;
		P[0][v] = par;
		L[v] = l;

		for (int i = 0; i < (int)E[v].size(); i++) {
			int w = E[v][i];
			int lc = 1;
			if (w == par) continue;
			dfs(w, v, d + 1, lc + l);
		}
	}

	void build() {
		for (int k = 0; k + 1 < logNV; k++) {
			for (int v = 0; v < NV; v++) {
				if (P[k][v] < 0) P[k + 1][v] = -1;
				else P[k + 1][v] = P[k][P[k][v]];
			}
		}
	}

	int query(int u, int v) {
		if (D[u] > D[v]) swap(u, v);
		for (int k = 0; k < logNV; k++) {
			if ((D[v] - D[u]) >> k & 1)
				v = P[k][v];
		}
		if (u == v) return u;

		for (int k = logNV - 1; k >= 0; k--) {
			if (P[k][u] != P[k][v]) {
				u = P[k][u];
				v = P[k][v];
			}
		}
		return P[0][u];
	}
};
//-----------------------------------------------------------------
int main() {
	scanf("%d", &N);
	rep(i, 0, N - 1) {
		int a, b; scanf("%d %d", &a, &b);
		E[a].push_back(b);
		E[b].push_back(a);
	}
	rep(i, 0, N) scanf("%d", &U[i]);

	bfs();

	LCA lca(N);
	lca.init();

	int M; scanf("%d", &M);
	ll ans = 0;
	rep(i, 0, M) {
		int a, b, c; scanf("%d %d %d", &a, &b, &c);

		int p = lca.query(a, b);
		ans += (sum[a] + sum[b] - sum[p]) * c;
	}
	printf("%lld\n", ans);
}