#include <bits/stdc++.h>

using namespace std;

template <typename T>
struct graph {
    struct edge {
        int from;
        int to;
        T cost;
    };

    vector<edge> edges;
    vector<vector<int>> g;
    int n;
    graph(int m) : n(m) {
        g.resize(n);
    }

    virtual int add(int from, int to, T cost) = 0;
};
template <typename T>
struct tree : graph<T> {
    using graph<T>::edges;
    using graph<T>::g;
    using graph<T>::n;
    tree(int m) : graph<T>(m) {}

    int add(int from, int to, T cost = 1) {
        assert(0 <= from && from < n && 0 <= to && to < n);
        int id = (int)edges.size();
        assert(id < n - 1);
        g[from].push_back(id);
        g[to].push_back(id);
        edges.push_back({from, to, cost});
        return id;
    }
};
template <typename T>
struct dfs_tree : tree<T> {
    using tree<T>::edges;
    using tree<T>::g;
    using tree<T>::n;

    vector<int> pv;
    vector<int> pe;
    vector<int> order;
    vector<int> pos;
    vector<int> end;
    vector<int> sz;
    vector<int> root;
    vector<int> depth;
    vector<T> dist;

    dfs_tree(int m) : tree<T>(m) {}

    void init() {
        pv = vector<int>(n, -1);
        pe = vector<int>(n, -1);
        order.clear();
        pos = vector<int>(n, -1);
        end = vector<int>(n, -1);
        sz = vector<int>(n, 0);
        root = vector<int>(n, -1);
        depth = vector<int>(n, -1);
        dist = vector<T>(n);
    }

    void clear() {
        pv.clear();
        pe.clear();
        order.clear();
        pos.clear();
        end.clear();
        sz.clear();
        root.clear();
        depth.clear();
        dist.clear();
    }

    void dfs(int v, bool clear_order = true) {
        if(pv.empty()) init();
        else if(clear_order) order.clear();
        dfs_from(v);
    }

  private:
    void _dfs(int v) {
        pos[v] = (int)order.size();
        order.push_back(v);
        sz[v] = 1;
        for(int id : g[v]) {
            if(id == pe[v]) continue;
            auto &e = edges[id];
            int to = e.from ^ e.to ^ v;
            depth[to] = depth[v] + 1;
            dist[to] = dist[v] + e.cost;
            pv[to] = v;
            pe[to] = id;
            root[to] = (root[v] != -1 ? root[v] : to);
            _dfs(to);
            sz[v] += sz[to];
        }
        end[v] = (int)order.size() - 1;
    }

    void dfs_from(int v) {
        depth[v] = 0;
        dist[v] = T{};
        root[v] = v;
        pv[v] = pe[v] = -1;
        _dfs(v);
    }
};
template <typename T>
struct lca_tree : dfs_tree<T> {
    using dfs_tree<T>::edges;
    using dfs_tree<T>::g;
    using dfs_tree<T>::n;
    using dfs_tree<T>::pv;
    using dfs_tree<T>::pos;
    using dfs_tree<T>::end;
    using dfs_tree<T>::depth;

    int h;
    vector<vector<int>> pr;

    lca_tree(int m) : dfs_tree<T>(m) {}

    inline void build_lca() {
        assert(!pv.empty());
        int max_depth = 0;
        for(int i = 0; i < n; i++) max_depth = max(max_depth, depth[i]);

        h = 1;
        while((1 << h) <= max_depth) h++;

        pr.resize(n);
        for(int i = 0; i < n; i++) {
            pr[i].resize(h);
            pr[i][0] = pv[i];
        }

        for(int j = 1; j < h; j++) {
            for(int i = 0; i < n; i++) {
                pr[i][j] = (pr[i][j - 1] == -1 ? -1 : pr[pr[i][j - 1]][j - 1]);
            }
        }
    }

    inline bool anc(int x, int y) {
        return (pos[x] <= pos[y] && end[y] <= end[x]);
    }

    inline int go_up(int x, int up) {
        assert(!pr.empty());
        up = min(up, (1 << h) - 1);
        for(int j = h - 1; j >= 0; j--) {
            if(up & (1 << j)) {
                x = pr[x][j];
                if(x == -1) break;
            }
        }
        return x;
    }

    inline int lca(int x, int y) {
        assert(!pr.empty());
        if(anc(x, y)) return x;
        if(anc(y, x)) return y;
        for(int j = h - 1; j >= 0; j--) {
            if(pr[x][j] != -1 && !anc(pr[x][j], y)) {
                x = pr[x][j];
            }
        }
        return pr[x][0];
    }
};
int main() {
    int n; cin >> n;
    lca_tree<long long> G(n);
    vector<pair<int, int>> edges;
    for(int i = 1; i < n; i++) {
        int a, b; cin >> a >> b;
        edges.push_back({a, b});
    }
    vector<long long> W(n);
    for(int i = 0; i < n; i++) cin >> W[i];
    for(int i = 0; i < n - 1; i++) {
        auto [a, b] = edges[i];
        G.add(a, b, W[a] + W[b]);
    }
    G.dfs(0);
    G.build_lca();
    long long ans = 0;
    int m; cin >> m;
    auto dist = [&](int a, int b) -> long long {
        return G.dist[a] + G.dist[b] - 2 * G.dist[G.lca(a, b)];
    };
    while(m--) {
        int a, b, c; cin >> a >> b >> c;
        ans += (dist(a, b) + W[a] + W[b])/2 * c;
    }
    cout << ans << endl;
}