import sys
input = sys.stdin.readline
from collections import deque

def bfs():
    dist = [-1] * N
    dist[0] = D[0]
    depth = [0] * N
    q = deque([])
    q.append(0)
    
    while q:
        cn = q.popleft()
        
        for nn in adj_list[cn]:
            if dist[nn] == -1:
                parents[0][nn] = cn
                dist[nn] = dist[cn]+D[nn]
                depth[nn] = depth[cn]+1
                q.append(nn)
    
    return dist, depth

def lca(u, v):
    if depth[u] > depth[v]:
        u, v = v, u
    
    for k in range(log_size):
        if ((depth[v]-depth[u])>>k)&1:
            v = parents[k][v]
    
    if u == v:
        return u
    
    for k in range(log_size-1, -1, -1):
        if parents[k][u] != parents[k][v]:
            u = parents[k][u]
            v = parents[k][v]
    
    return parents[0][u]
    
    
N = int(input())
adj_list = [[] for _ in range(N)]

for _ in range(N-1):
    A, B = map(int, input().split())
    adj_list[A].append(B)
    adj_list[B].append(A)
    
D = [int(input()) for _ in range(N)]
log_size = N.bit_length()
parents = [[-1] * N for _ in range(log_size)]
dist, depth = bfs()

for i in range(1, log_size):
    for j in range(N):
        parents[i][j] = parents[i-1][parents[i-1][j]]

M = int(input())
ans = 0

for _ in range(M):
    A, B, C = map(int, input().split())
    L = lca(A, B)
    ans += (dist[A]+dist[B]-2*dist[L]+D[L])*C

print(ans)