#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>
#define repd(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repd(i,0,n)
#define all(x) (x).begin(),(x).end()
#define mod 1000000007
#define inf 2000000007
#define mp make_pair
#define pb push_back
typedef long long ll;
using namespace std;
template <typename T>
inline void output(T a, int p) {
    if(p) cout << fixed << setprecision(p)  << a << "\n";
    else cout << a << "\n";
}
// end of template

// least common ancestor
class LCA{
public:
    int V;
    int logV, id = 0;
    vector<vector<pair<int, int>>> G; // graph: vertex, distance
    vector<int> depth, dist;
    vector<vector<int>> parent;
    vector<int> L, R, I;
    
    LCA(int n){
        V = n;
        G.resize(V);
        depth.resize(V);
        dist.resize(V);
        L.resize(V), R.resize(V), I.resize(V);
        logV = 0;
        while (V >= (1 << logV)) logV++;
        parent.resize(logV, vector<int>(V));
        
    }
    
    // determine depth and distance from root
    void init(int v = 0, int par = -1, int d = 0, int l = 0) { // root: v = 0, init(0, -1, 0, 0)
        depth[v] = d;
        parent[0][v] = par;
        dist[v] = l;
        I[id] = v;
        L[v] = id++;
        rep(i, G[v].size()){
            int w = G[v][i].first;
            int lc = G[v][i].second;
            if (w == par) continue;
            init(w, v, d + 1, lc + l);
        }
        R[v] = id;
    }
    
    void build() {
        for (int k = 0; k + 1 < logV; k++) {
            for (int v = 0; v < V; v++) {
                if (parent[k][v] < 0) parent[k+1][v] = -1;
                else parent[k+1][v] = parent[k][parent[k][v]];
            }
        }
    }
    
    void add(int v1, int v2, int dist = 0){
        G[v1].pb(mp(v2, dist));
        G[v2].pb(mp(v1, dist));
    }
    
    int query(int u, int v) {
        if (depth[u] > depth[v]) swap(u, v);
        for (int k = 0; k < logV; k++) {
            if ((depth[v] - depth[u]) >> k & 1)
                v = parent[k][v];
        }
        if (u == v) return u;
        
        for (int k = logV - 1; k >= 0; k--) {
            if (parent[k][u] != parent[k][v]) {
                u = parent[k][u];
                v = parent[k][v];
            }
        }
        return parent[0][u];
    }
    
};

vector<int> dist;

void dfs(vector<vector<pair<int, int>>> &G, vector<int> &U, int pre = -1, int cur = 0, int cost = 0){
    dist[cur] = cost + U[cur];
    for(auto v: G[cur]){
        if(v.first != pre){
            dfs(G, U, cur, v.first, dist[cur]);
        }
    }
}



int main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    // source code
    int N;
    cin >> N;
    LCA lca(N);
    rep(i, N - 1){
        int A, B;
        cin >> A >> B;
        lca.add(A, B);
    }
    lca.init();
    lca.build();
    auto G = lca.G;
    dist.resize(N);
    vector<int> U(N);
    rep(i, N) cin >> U[i];
    dfs(G, U);
    
    int M;
    cin >> M;
    ll ret = 0;
    rep(i, M){
        int A, B, C;
        cin >> A >> B >> C;
        
        ret += (ll)(dist[A] + dist[B] - 2 * dist[lca.query(A, B)] + U[lca.query(A, B)]) * C;
//        cout << A << ", " << B << ": " << lca.query(A, B) << endl;
    }
    
    output(ret, 0);
    
    return 0;
}