import sys
sys.setrecursionlimit(10**6)
class LCA():
    
    def __init__(self,e,root=0):
        
        self.N = len(e)
        self.e = e
        self.root = root
        self.IN = [-1]*N
        self.OUT = [-1]*N
        self.DIST = [-1]*N
        self.time = 0
        self.DIST[root] = 0
        self.parents = [-1]*N
        self.dfs(root)
        self.depth = [(self.DIST[i],i) for i in range(N)]
        self.init_val = [-1]*(2*N)
        for i in range(N):
            x = self.IN[i]
            y = self.OUT[i]
            self.init_val[x] = self.depth[i]
            self.init_val[y] = self.depth[self.parents[i]]
        
        self.T = self.SegTree(self.init_val)
        
    def dfs(self,x):
        
        self.IN[x] = self.time
        self.time += 1
        for ix in e[x]:
            if self.DIST[ix] != -1:
                continue
            self.parents[ix] = x
            self.DIST[ix] = self.DIST[x] + 1
            self.dfs(ix)
            
        self.OUT[x] = self.time
        self.time += 1
        
    def lca(self,l,r):
        L = self.IN[l]
        R = self.IN[r]
        if R<L:
            L,R = R,L
        R += 1
        return self.T.query(L,R)[1]
        
        
    def distance_between(self,l,r):
        
        p = self.lca(l,r)
        return self.DIST[l]+ self.DIST[r] - 2*self.DIST[p]
        
    def distance_from_root(self,x):
        return self.DIST[x]

    class SegTree:
        """
        Segment Tree
        """
    
        def __init__(self, init_val, segfunc = None, ide_ele= None):
            """
            初期化
            
            init_val: 配列の初期値
            """
            if segfunc is None:
                def segfunc(x,y):
                    return min(x,y)
                ide_ele = (float('inf'),-1)
                
            
            n = len(init_val)
            self.segfunc = segfunc
            self.ide_ele = ide_ele
            self.num = 1 << (n - 1).bit_length()
            self.tree = [ide_ele] * 2 * self.num
            # 配列の値を葉にセット
            for i in range(n):
                self.tree[self.num + i] = init_val[i]
            # 構築していく
            for i in range(self.num - 1, 0, -1):
                self.tree[i] = segfunc(self.tree[2 * i], self.tree[2 * i + 1])
    
        def update(self, k, x):
            """
            k番目の値をxに更新
    
            k: index(0-index)
            x: update value
            """
            k += self.num
            self.tree[k] = x
            while k > 1:
                self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
                k >>= 1
    
        def query(self, l, r):
            """
            [l, r)のsegfuncしたものを得る
    
            l: index(0-index)
            r: index(0-index)
            """
            res = self.ide_ele
    
            l += self.num
            r += self.num
            while l < r:
                if l & 1:
                    res = self.segfunc(res, self.tree[l])
                    l += 1
                if r & 1:
                    res = self.segfunc(res, self.tree[r - 1])
                l >>= 1
                r >>= 1
            return res        
            
N = int(input())
e = [[] for _ in range(N)]
for _ in range(N-1):
    a,b = map(int,input().split())
    e[a].append(b)
    e[b].append(a)

U = [int(input()) for _ in range(N)]

W = [-1]*N
tW = 0
def dfs(x):
    global tW
    tW += U[x]
    W[x] = tW
    for ix in e[x]:
        if W[ix] != -1:
            continue
        dfs(ix)
    tW -= U[x]
    
dfs(0)
L = LCA(e)
ans = 0
M = int(input())
for _ in range(M):
    a,b,c = map(int,input().split())
    p = L.lca(a,b)
    ans += c*(W[a] + W[b] - 2*W[p] + U[p])
print(ans)