class LCA:
    def __init__(self, graph, weight, root=0):
        self.tree = graph
        self.root = root
        self.n = len(graph)
        self.weight = weight
        self.k = self._get_bit()
        self.dist = [-1]*self.n
        self.parent = [[-1]*self.n for _ in range(self.k)]
        self._dfs()
        self._doubling()

    def _get_bit(self):
        k = 1
        while (1<<k)<self.n: k += 1
        return k
    
    def _dfs(self):
        self.dist[self.root] = 0
        stack = [self.root]
        while stack:
            u = stack.pop()
            for v in self.tree[u]:
                if self.dist[v]!=-1:
                    continue
                self.dist[v] = self.dist[u]+1
                self.weight[v] += self.weight[u]
                self.parent[0][v] = u
                stack.append(v)

    def _doubling(self):
        for i in range(self.k-1):
            for j in range(self.n):
                if self.parent[i][j]<0:
                    self.parent[i+1][j] = -1
                else:
                    self.parent[i+1][j] = self.parent[i][self.parent[i][j]]

    def query(self, u, v):
        if self.dist[u]<self.dist[v]:
            u, v = v, u
        for i in range(self.k):
            if (self.dist[u]-self.dist[v])>>i&1:
                u = self.parent[i][u]
        if u==v:
            return u
        for i in reversed(range(self.k)):
            if self.parent[i][u]!=self.parent[i][v]:
                u = self.parent[i][u]
                v = self.parent[i][v]
        return self.parent[0][u]
    
    def get_dist(self, u, v):
        return self.dist[u]+self.dist[v]-2*self.dist[self.query(u, v)]

    def get_weight(self, u, v):
        a = self.query(u, v)
        pa = self.kth_ancestor(a, 1)
        pw = self.weight[pa]
        if pa==-1:
            pw = 0
        return self.weight[u]+self.weight[v]-self.weight[a]-pw
    
    def is_on_path(self, u, v, a):
        return self.get_dist(u, a)+self.get_dist(a, v)==self.get_dist(u, v)
    
    def kth_ancestor(self, u, k):
        for i in range(self.k):
            if (k>>i)&1:
                u = self.parent[i][u]
                if u == -1:
                    break
        return u
    
if __name__=='__main__':
    n = int(input())
    g = [[] for _ in range(n)]
    for _ in range(n-1):
        a, b = map(int, input().split())
        g[a].append(b)
        g[b].append(a)
    u = [int(input()) for _ in range(n)]
    lca = LCA(g, u)
    ans = 0
    for _ in range(int(input())):
        a, b, c = map(int, input().split())
        ans += lca.get_weight(a, b)*c
    print(ans)