#include <iostream>
#include <vector>
using namespace std;

typedef unsigned long long ULL;

#define MAXN (100000+1)
#define MAXM (200000+1)

ULL N, M, A, B, C, TOTAL;
vector<int> tree[MAXN];
ULL cost[MAXN];
pair<int,int> lca[MAXN];

void build(int n, int p, int depth)
{
    lca[n] = make_pair(p, depth);
    for (int i = 0; i < tree[n].size(); i++) {
        if (tree[n][i] != p) {
            build(tree[n][i], n, depth+1);
        }
    }
}

ULL solve(int a, int b)
{
    ULL aa = 0;
    ULL bb = 0;
    while (1) {
        if (a == b) {
            return aa + bb + cost[a];
        }
        else if (lca[a].second > lca[b].second) {
            aa += cost[a];
            a = lca[a].first;
        }
        else {
            bb += cost[b];
            b = lca[b].first;
        }
    }
    return 0;
}

int main()
{
    cin >> N;
    for (int n = 0; n < (N-1); n++) {
        cin >> A;
        cin >> B;
        tree[A].push_back(B);
        tree[B].push_back(A);
    }
    for (int n = 0; n < N; n++) {
        cin >> cost[n];
    }
    build(0, -1, 0);

    cin >> M;
    for (int m = 0; m < M; m++) {
        cin >> A;
        cin >> B;
        cin >> C;
        TOTAL += solve(A, B) * C;
    }
    cout << TOTAL << endl;
}