def data_setting():
	N = int(input())
	tree = []
	tree_line = [list(map(int,input().split())) for i in range(N-1)]
	for i in range(N):
		tree_tmp = []
		for j in range(len(tree_line)):
			if tree_line[j][0] == i:
				tree_tmp.append(tree_line[j][1])
			elif tree_line[j][1] == i:
				tree_tmp.append(tree_line[j][0])
		tree.append(tree_tmp)
	tax = [int(input()) for i in range(N)]
	M = int(input())
	group = [list(map(int,input().split())) for i in range(M)]
	return M,tree,tax,group
def disp(M,tree,tax,group):
	print(tree)
	print(tax)
	print(M)
	print(group)
def route_cal(start):
	now = start
	route =[]
	while now != 0:
		route.append(now)
		now = min(tree[now])
	route.append(0)
	print(route)
	return route
def cal(M,tree,tax,group):
	ans = 0
	for i in range(M):
		print("group",i)
		A = group[i][0]
		B = group[i][1]
		C = group[i][2]
		routeA = route_cal(A)
		routeB = route_cal(B)
		junction = []
		for j in range(len(routeA)):
			if routeA[j] in routeB:
				junction.append(routeA[j])
		P = max(junction)
		route = routeA[:routeA.index(P)+1] + routeB[:routeB.index(P)]
		pay_tax = 0
		for k in range(len(route)):
			pay_tax += (tax[route[k]] * C)
		ans += pay_tax
	return ans
M,tree,tax,group = data_setting()
disp(M,tree,tax,group)
ans = cal(M,tree,tax,group)
print(ans)