#include <iostream>
#include <vector>
#include <queue>
using namespace std;
using ll = long long;

struct LCA{
    vector<vector<int>> parent;
    vector<int> dist;

    LCA(const vector<vector<int>> &G, int root = 0){
        init(G, root);
    }

    void init(const vector<vector<int>> &G, int root = 0){
        dist.assign(G.size(), -1);
        int k = 1;
        for(; (1 << k) < G.size(); k++);
        parent.assign(k, vector<int>(G.size(), -1));

        queue<int> Q;
        dist[root] = 0;
        Q.emplace(root);
        while(!Q.empty()){
            int c = Q.front(); Q.pop();
            for(const auto &nex: G[c]){
                if(dist[nex] != -1) continue;
                dist[nex] = dist[c]+1;
                parent[0][nex] = c;
                Q.emplace(nex);
            }
        }
        for(int i = 1; i < parent.size(); i++){
            for(int v = 0; v < G.size(); v++){
                if(parent[i-1][v] < 0) parent[i][v] = 0;
                else parent[i][v] = parent[i-1][parent[i-1][v]];
            }
        }
    }

    int query(int u, int v){
        if(dist[u] < dist[v]) swap(u, v);
        for(int i = 0; i < parent.size(); i++){
            if((dist[u]-dist[v]) >> i & 1){
                u = parent[i][u];
            }
        }

        if(u == v) return u;
        for(int i = parent.size()-1; i >= 0; i--){
            if(parent[i][u] != parent[i][v]){
                u = parent[i][u];
                v = parent[i][v];
            }
        }
        return parent[0][u];
    }
};

int main(){
    int n; cin >> n;
    vector<vector<int>> G(n);
    for(int i = 0; i < n-1; i++){
        int a, b; cin >> a >> b;
        G[a].emplace_back(b);
        G[b].emplace_back(a);
    }
    vector<int> u(n);
    for(auto &it: u) cin >> it;

    LCA lca(G);
    vector<int> cost(n, -1);
    cost[0] = u[0];
    queue<int> Q;
    Q.emplace(0);
    while(!Q.empty()){
        int c = Q.front(); Q.pop();
        for(auto const &nex: G[c]){
            if(cost[nex] != -1) continue;
            cost[nex] = cost[c]+u[nex];
            Q.emplace(nex);
        }
    }

    int m; cin >> m;
    ll ans = 0;
    while(m--){
        int a, b, c; cin >> a >> b >> c;
        ans += (ll)(cost[a]+cost[b]-2*cost[lca.query(a, b)]+u[lca.query(a, b)])*c;
    }
    cout << ans << endl;
    return 0;
}