from collections import deque

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)]

src = 0
depth = [None for _ in range(n)]
depth[src] = 0
dq = deque()
dq.appendleft(src)
k = n.bit_length()
doub = [[None for _ in range(n)] for _ in range(k)]
doub[0][src] = src

cost = [0 for _ in range(n)]
cost[src] = u[src]
while len(dq) > 0:
  cur = dq.pop()
  for nxt in g[cur]:
    if not depth[nxt] is None:
      continue
    depth[nxt] = depth[cur] + 1
    cost[nxt] = cost[cur] + u[nxt]
    doub[0][nxt] = cur
    dq.appendleft(nxt)

for i in range(1, k):
  for v in range(n):
    doub[i][v] = doub[i - 1][doub[i - 1][v]]

def lca(u, v):
  ut = u
  vt = v

  if depth[ut] > depth[vt]:
    ut, vt = vt, ut

  diff = depth[vt] - depth[ut]
  for i in range(k):
    if (diff >> i) & 1 != 0:
      vt = doub[i][vt]

  if ut != vt:
    for i in range(depth[ut].bit_length() - 1, -1, -1):
      if doub[i][ut] != doub[i][vt]:
        ut = doub[i][ut]
        vt = doub[i][vt]

    if ut != vt:
      ut = doub[0][ut]

  return ut

ans = 0
m = int(input())
for _ in range(m):
  a, b, c = map(int, input().split())
  l = lca(a, b)
  ans += c * (cost[a] + cost[b] - 2 * cost[l] + u[l])

print(ans)