import collections


class LCA:
    def __init__(self, n, adj, us):
        K = 1
        while (1 << K) < n: K += 1
        self.parent = [[-1] * n for _ in range(K)]
        self.dist = [-1] * n
        self.cost = [-1] * n
        self._dfs2(node=0, par=-1, d=0, adj=adj, us=us)
        for k in range(K-1):
            for v in range(n):
                if self.parent[k][v] < 0:
                    self.parent[k+1][v] = -1
                else:
                    self.parent[k+1][v] = self.parent[k][self.parent[k][v]]

    def _dfs2(self, node, par, d, adj, us):
        s = [(node, par, d, us[node])]
        while s:
            node, par, d, c = s.pop()
            self.parent[0][node] = par
            self.dist[node] = d
            self.cost[node] = c
            for nd in adj[node]:
                if nd == par: continue
                s.append((nd, node, d + 1, c + us[nd]))

    def query(self, u: int, v: int) -> int:
        if self.dist[u] < self.dist[v]: u, v = v, u
        K = len(self.parent)
        # LCA までの距離を同じにする
        for k in range(K):
            if (self.dist[u] - self.dist[v]) >> k & 1:
                u = self.parent[k][u]
        # 二分探索で LCA を求める
        if u == v: return u
        for k in range(K-1, -1, -1):
            if self.parent[k][u] != self.parent[k][v]:
                u = self.parent[k][u]
                v = self.parent[k][v]
        return self.parent[0][u]

    def distance(self, u: int, v: int) -> int:
        return self.dist[u] + self.dist[v] - 2 * self.dist[self.query(u, v)]

    def get_cost(self, u: int, v: int) -> int:
        return self.cost[u] + self.cost[v] - 2 * self.cost[self.query(u, v)]

    def is_on_path(self, u, v, a) -> bool:
        return self.distance(u, a) + self.distance(a, v) == self.distance(u, v)


import sys
input = sys.stdin.readline
N = int(input())
adj = collections.defaultdict(list)
for i in range(N-1):
    a, b = map(int, input().split())
    adj[a].append(b)
    adj[b].append(a)

us = []
for i in range(N):
    us.append(int(input()))

Q = int(input())
lca = LCA(N, adj, us)
ans = 0
for _ in range(Q):
    a, b, c = map(int, input().split())
    lca_node = lca.query(a, b)
    cost = lca.cost[a] + lca.cost[b] - 2 * lca.cost[lca_node] + us[lca_node]
    ans += cost * c
print(ans)