#define PROBLEM "https://yukicoder.me/problems/no/386"

#include <bits/stdc++.h>
using namespace std;

template<class T>
struct LowestCommonAncestor{
    vector<vector<int>> parent;
    vector<int> height;
    vector<T> dist;
    LowestCommonAncestor(const vector<vector<pair<int, T>>>& G, int root=0) {
        init(G, root);
    }

    void init(const vector<vector<pair<int, T>>>& G, int root=0) {
        int N = G.size();
        int M = 1; while((1 << M) < N) M++;
        parent.assign(M, vector<int>(N, -1));
        height.assign(N, -1);
        dist.assign(N, -1);
        dfs(G, root, -1, 0, 0);
        for(int lv = 1; lv < M; lv++) {
            for(int i = 0; i < N; i++) {
                if(parent[lv - 1][i] == -1) parent[lv][i] = -1;
                else parent[lv][i] = parent[lv - 1][parent[lv - 1][i]];
            }
        }
    }

    void dfs(const vector<vector<pair<int, T>>>& G, int v, int p, int h, T d) {
        parent[0][v] = p;
        height[v] = h;
        dist[v] = d;
        for(auto [nv, c] : G[v]) {
            if(nv == p) continue;
            dfs(G, nv, v, h + 1, d + c);
        }
    }

    int lca(int u, int v) {
        if(height[u] < height[v]) swap(u, v);
        int M = parent.size();
        for(int lv = 0; lv < M; lv++) {
            if(((height[u] - height[v]) >> lv) & 1) u = parent[lv][u];
        }
        if(u == v) return u;
        for(int lv = M - 1; lv >= 0; lv--) {
            if(parent[lv][u] != parent[lv][v]) {
                u = parent[lv][u];
                v = parent[lv][v];
            }
        }
        return parent[0][u];
    }

    T dist_bitween(int u, int v) { return dist[u] + dist[v] - 2 * dist[lca(u, v)]; }

    int path_len(int u, int v) { return height[u] + height[v] - 2 * height[lca(u, v)]; }
};


int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int N;
    cin >> N;
    vector<int> A(N - 1), B(N - 1);
    for(int i = 0; i < N - 1; i++) {
        cin >> A[i] >> B[i];
    }
    vector<int> C(N);
    for(int i = 0; i < N; i++) {
        cin >> C[i];
    }

    vector<vector<pair<int, int>>> G(N);
    for(int i = 0; i < N - 1; i++) {
        G[A[i]].push_back({B[i], C[A[i]] + C[B[i]]});
        G[B[i]].push_back({A[i], C[A[i]] + C[B[i]]});
    }
    LowestCommonAncestor<int> lca(G);

    int M;
    cin >> M;
    long long ans = 0;
    while(M--) {
        int a, b, c;
        cin >> a >> b >> c;
        int tax = lca.dist_bitween(a, b) + C[a] + C[b];
        tax = tax / 2 * c;
        ans += tax;
    }
    cout << ans << endl;

    return 0;
}