#include <iostream>
#include <vector>
#include <queue>
using namespace std;
int main(){
    int n;
    cin >> n;
    vector<vector<int>> graph(n);
    for(int i=1; i<n; ++i){
        int a, b;
        cin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    vector<int> u(n);
    for(int &i: u)
        cin >> i;
    int maxlog = 0;
    while((1<<maxlog) <= n) 
        ++maxlog;
    vector<vector<int>> parent(n, vector<int>(maxlog));
    vector<int> cost(u), depth(n);
    queue<int> que;
    que.push(0);
    while(!que.empty()){
        int i = que.front();
        que.pop();
        for(int j: graph[i]){
            if(j == parent[i][0])
                continue;
            parent[j][0] = i;
            depth[j] = depth[i] + 1;
            cost[j] += cost[i];
            que.push(j);
        }
    }
    for(int i=1; i<maxlog; ++i)
        for(int j=0; j<n; ++j)
            parent[j][i] = parent[parent[j][i-1]][i-1];
    int m;
    cin >> m;
    long long res = 0;
    for(int i=0; i<m; ++i){
        int a, b, c;
        cin >> a >> b >> c;
        res += (cost[a] + cost[b]) * c;
        if(depth[a] > depth[b])
            swap(a, b);
        for(int i=maxlog-1; i>=0; --i)
            if(depth[parent[b][i]] >= depth[a])
                b = parent[b][i];
        if(a != b){
            for(int i=maxlog-1; i>=0; --i)
                if(parent[a][i] != parent[b][i]){
                    a = parent[a][i];
                    b = parent[b][i];
                }
            a = parent[a][0];
        }
        res -= (cost[a]*2 - u[a]) * c;
    }
    cout << res << endl;
    return 0;
}