package yukicoder;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		new Main().solver();
	}

	@SuppressWarnings("unchecked")
	void solver() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		edges = new ArrayList[N];
		for (int i = 0; i < N; i++) {
			edges[i] = new ArrayList<>();
		}
		for (int i = 0; i < N - 1; i++) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			edges[a].add(b);
			edges[b].add(a);
		}
		init(N);

		int[] u = new int[N];
		for (int i = 0; i < N; i++) {
			u[i] = sc.nextInt();
		}

		init2(u);
		int M = sc.nextInt();

		long ans = 0;
		for (int i = 0; i < M; i++) {
			int f = sc.nextInt();
			int t = sc.nextInt();
			int c = sc.nextInt();
			int lca = lca(f, t);
			int ret = cost(lca, f) + cost(lca, t) - u[lca];
			ans += ret * c;
		}
		System.out.println(ans);
		
	}

	int MAX_LOG_V;// =(int)log2(MAX_V)+1
	int MAX_V;
	int root;// 根ノードの番号
	int parent[][];// [MAX_LOG_V + 1][MAX_V]
	// parent[k][v] 2^k回親を辿ったときに到達する頂点（根を通り過ぎたときは-1）
	int[] depth;// [MAX_V] 根からの深さ
	ArrayList<Integer> edges[];

	void init(int N) {
		// 変数の用意
		MAX_V = N;
		MAX_LOG_V = (int) (Math.log(MAX_V) / Math.log(2)) + 1;
		root = 0;
		parent = new int[MAX_LOG_V + 1][MAX_V];
		depth = new int[MAX_V];
		cost = new int[MAX_LOG_V + 1][MAX_V];// cost[k][v]
		// 頂点vから(2^k-1)回親を辿ったときにかかるお金
		// parent[0]とdepthを初期化する
		bfs(root, -1, 0);
		// parentを初期化する
		for (int k = 0; k < MAX_LOG_V; k++) {
			for (int v = 0; v < MAX_V; v++) {
				if (parent[k][v] < 0) {
					parent[k + 1][v] = -1;
				} else {
					parent[k + 1][v] = parent[k][parent[k][v]];
				}
			}
		}
	}

	class P {
		int parent;
		int me;
		int depth;

		P(int me, int parent, int depth) {
			this.me = me;
			this.parent = parent;
			this.depth = depth;
		}
	}

	// dfsだとstack over flow が怖いのでbfs
	void bfs(int v, int p, int d) {
		ArrayDeque<P> q = new ArrayDeque<P>();
		q.add(new P(v, p, d));
		while (!q.isEmpty()) {
			P u = q.poll();
			parent[0][u.me] = u.parent;
			depth[u.me] = u.depth;
			for (int i = 0; i < edges[u.me].size(); i++) {
				if (edges[u.me].get(i) != u.parent)
					q.add(new P(edges[u.me].get(i), u.me, u.depth + 1));
			}
		}
	}

	int lca(int u, int v) {
		// uとvの深さが同じになるまで親を辿る
		if (depth[u] > depth[v]) {
			int d = u;
			u = v;
			v = d;
		}
		// depth[v]-depth[u]>=2^kとなる最小のkを求める。
		// つまりuをvと深さが同じか小さいぎりぎりのところまで親を辿る。
		for (int k = 0; k < MAX_LOG_V; k++) {
			if ((((depth[v] - depth[u]) >> k) & 1) == 1) {
				v = parent[k][v];
			}
		}
		if (u == v)
			return u;
		// uとvが衝突しないように辿る。
		for (int k = MAX_LOG_V - 1; k >= 0; k--) {
			if (parent[k][u] != parent[k][v] && parent[k][u] != -1 && parent[k][v] != -1) {
				u = parent[k][u];
				v = parent[k][v];
			}
		}
		return parent[0][u];
	}

	int[][] cost;// cost[k][v] 頂点vから(2^k-1)回親を辿ったときにかかるお金

	void init2(int[] u) {
		// cost[0][v]を初期化する

		for (int i = 0; i < MAX_V; i++) {
			cost[0][i] = u[i];
		}
		// parentを初期化する
		for (int k = 0; k < MAX_LOG_V; k++) {
			for (int v = 0; v < MAX_V; v++) {
				if (parent[k][v] == -1) {
					cost[k + 1][v] = Integer.MAX_VALUE / 4;
				} else {
					cost[k + 1][v] = cost[k][parent[k][v]] + cost[k][v];
				}
			}
		}
	}

	int cost(int c, int p) {
		if (depth[c] < depth[p]) {
			int d = c;
			c = p;
			p = d;
		}

		int d = depth[c] - depth[p] + 1;
		int sum = 0;
		for (int i = 0; d > 0; d >>= 1, i++) {
			if ((d & 1) == 1) {
				sum += cost[i][c];
				if (cost[i][c] >= Integer.MAX_VALUE / 4)
					throw new AssertionError("error");
				if (parent[i][c] != -1) {
					c = parent[i][c];
				}
			}
		}
		return sum;
	}
	void tr(Object...o){System.out.println(Arrays.deepToString(o));}
	private static class Scanner{
		BufferedReader br;
		Iterator<String> it;
		Scanner(InputStream in){
			br=new BufferedReader(new InputStreamReader(in));
		}
		String next()throws RuntimeException{
			try{
				if(it==null||!it.hasNext())
					it=Arrays.asList(br.readLine().split(" ")).iterator();
				return it.next();
			}catch(IOException e){
				throw new IllegalStateException();
			}
		}
		int nextInt() throws RuntimeException{
			return Integer.parseInt(next());
		}
		long nextLong() throws RuntimeException{
			return Long.parseLong(next());
		}
		double nextDouble() throws RuntimeException{
			return Double.parseDouble(next());
		}
		void close(){
			try{
				br.close();
			}catch(IOException e){
				throw new IllegalStateException();
			}
		}
	}
	private static class Printer extends PrintWriter{
		Printer(PrintStream out){
			super(out);
		}
	}
}