using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Runtime.CompilerServices;
using System.Text;
using static Template;
using static System.Console;
using static System.Convert;
using static System.Math;
using Pi = Pair<int, int>;
using Number = System.Int64;

class Solver
{
    public void Solve()
    {
        var num = Input.num;
        var lca = new LowestCommonAncestor(num);
        for(var i=0;i<num-1;i++)
        {
            int a, b;
            Input.Make(out a, out b);
            lca.AddEdge(a, b);
        }
        lca.cs = Input.arL1D(num);
        var m = Input.num;
        lca.Build();var res = 0L;
        while (m-- > 0)
        {
            int a, b, c;
            Input.Make(out a, out b, out c);
            res += c * lca.LCA(a, b);
        }WriteLine(res);

    }
}

class LowestCommonAncestor
{
    private List<int>[] edge;
    private int num, lb;
    private int[][] parent;
    private int[] depth;
    public long[] cs;
    long[][] dist;
    public LowestCommonAncestor(int num)
    { this.num = num; edge = Create(num, () => new List<int>()); }
    public void AddEdge(int u, int v)
    {
        edge[u].Add(v); edge[v].Add(u);
    }
    public void Build(int root = 0)
    {
        for (lb = 31; lb >= 0; lb--)
            if ((1 & num >> lb) == 1)
                break;
        parent = Create(lb + 1, () => Create(num, () => -1));
        dist = Create(lb + 1, () => Create(num, () => -1L));
        dist[0] = cs;
        depth = new int[num];
        PreDFS(root, -1);
        for (var i = 1; i <= lb; i++)
            for (var j = 0; j < num; j++)
                if (parent[i - 1][j] != -1)
                {
                    parent[i][j] = parent[i - 1][parent[i - 1][j]];
                    dist[i][j] = dist[i - 1][j] + dist[i - 1][parent[i - 1][j]];
                }
    }
    private void PreDFS(int index, int p)
    {
        parent[0][index] = p;
        foreach (var e in edge[index])
            if (e != p)
            {
                depth[e] = depth[index] + 1;
                PreDFS(e, index);
            }
    }
    public long LCA(int u, int v)
    {
        if (depth[u] > depth[v])
            swap(ref u, ref v);
        var rt = 0L;
        for (var i = lb; i >= 0; i--)
            if ((1 & (depth[v] - depth[u]) >> i) == 1)
            { rt += dist[i][v]; v = parent[i][v]; }
        if (u == v) return rt + cs[u];
        for (var i = lb; i >= 0; i--)
            if (parent[i][u] != parent[i][v])
            { rt += dist[i][u] + dist[i][v]; u = parent[i][u]; v = parent[i][v]; }
        return rt + dist[1][u] + dist[0][v];
    }
}
#region Template
public class Template
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static bool chmin<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == 1) { num = val; return true; } return false; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static bool chmax<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == -1) { num = val; return true; } return false; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static void swap<T>(ref T v1, ref T v2)
    { var t = v2; v2 = v1; v1 = t; }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static T[] Create<T>(int n, Func<T> f)
        => Enumerable.Repeat(0, n).Select(_ => f()).ToArray();
    public static void Fail() => Fail("No");
    public static void Fail<T>(T s) { Console.WriteLine(s); Console.Out.Close(); Environment.Exit(0); }
    static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        var p = new Solver();
        for (var i = 1; i > 0; --i)
            p.Solve();
        Console.Out.Flush();
    }
}

public class Input
{
    public static string read => Console.ReadLine().Trim();
    public static int[] ar => read.Split(' ').Select(int.Parse).ToArray();
    public static int num => Convert.ToInt32(read);
    public static long[] arL => read.Split(' ').Select(long.Parse).ToArray();
    public static long numL => Convert.ToInt64(read);
    public static char[][] grid(int h)
        => Create(h, () => read.ToCharArray());
    public static int[] ar1D(int n)
        => Create(n, () => num);
    public static long[] arL1D(int n)
        => Create(n, () => numL);
    public static string[] strs(int n)
        => Create(n, () => read);
    public static int[][] ar2D(int n)
        => Create(n, () => ar);
    public static long[][] arL2D(int n)
        => Create(n, () => arL);
    public static List<T>[] edge<T>(int n)
        => Create(n, () => new List<T>());
    public static void Make<T1, T2>(out T1 v1, out T2 v2)
    {
        v1 = Next<T1>();
        v2 = Next<T2>();
    }
    public static void Make<T1, T2, T3>(out T1 v1, out T2 v2, out T3 v3)
    {
        Make(out v1, out v2);
        v3 = Next<T3>();
    }
    public static void Make<T1, T2, T3, T4>(out T1 v1, out T2 v2, out T3 v3, out T4 v4)
    {
        Make(out v1, out v2, out v3);
        v4 = Next<T4>();
    }
    public static void Make<T1, T2, T3, T4, T5>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5)
    {
        Make(out v1, out v2, out v3, out v4);
        v5 = Next<T5>();
    }
    public static void Make<T1, T2, T3, T4, T5, T6>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5, out T6 v6)
    {
        Make(out v1, out v2, out v3, out v4, out v5);
        v6 = Next<T6>();
    }
    private static Queue<string> sc = new Queue<string>();
    public static T Next<T>() { if (sc.Count == 0) foreach (var item in ReadLine().Split(' ')) sc.Enqueue(item); return (T)Convert.ChangeType(sc.Dequeue(), typeof(T)); }
    public const int MOD = 1000000007;
}

public class Pair<T1, T2> : IComparable<Pair<T1, T2>>
{
    public T1 v1;
    public T2 v2;
    public Pair() { v1 = default(T1); v2 = default(T2); }
    public Pair(T1 v1, T2 v2)
    { this.v1 = v1; this.v2 = v2; }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public int CompareTo(Pair<T1, T2> p)
    {
        var c = Comparer<T1>.Default.Compare(v1, p.v1);
        if (c == 0)
            c = Comparer<T2>.Default.Compare(v2, p.v2);
        return c;
    }
    public override string ToString()
        => $"{v1.ToString()} {v2.ToString()}";
}

public class Pair<T1, T2, T3> : Pair<T1, T2>, IComparable<Pair<T1, T2, T3>>
{
    public T3 v3;
    public Pair() : base() { v3 = default(T3); }
    public Pair(T1 v1, T2 v2, T3 v3) : base(v1, v2)
    { this.v3 = v3; }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public int CompareTo(Pair<T1, T2, T3> p)
    {
        var c = base.CompareTo(p);
        if (c == 0)
            c = Comparer<T3>.Default.Compare(v3, p.v3);
        return c;
    }
    public override string ToString()
        => $"{base.ToString()} {v3.ToString()}";
}
#endregion