import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {
  private static class Task {
    void solve(FastScanner in, PrintWriter out) {
      int N = in.nextInt();
      ArrayList<Integer>[] g = new ArrayList[N];
      for (int i = 0; i < N; i++) g[i] = new ArrayList<>();
      for (int i = 0; i < N - 1; i++) {
        int a = in.nextInt(), b = in.nextInt();
        g[a].add(b);
        g[b].add(a);
      }
      int[] U = in.nextIntArray(N);

      ArrayList<ArrayList<WeightedLCA.Edge>> graph = new ArrayList<>();
      for (int i = 0; i < N; i++) graph.add(new ArrayList<>());
      build(g, graph, U);

      WeightedLCA lca = new WeightedLCA(graph);
      long ans = 0;
      int Q = in.nextInt();
      for (; Q > 0; Q--) {
        int a = in.nextInt();
        int b = in.nextInt();
        long c = in.nextInt();
        int l = lca.getLCA(a, b);
        long dist = lca.getLength(a, b);
        dist = dist - U[l] + U[a] + U[b];
        ans += dist * c;
      }
      out.println(ans);

    }

    void build(ArrayList<Integer>[] g, ArrayList<ArrayList<WeightedLCA.Edge>> graph, int[] U) {
      ArrayDeque<Integer> deque = new ArrayDeque<>();
      boolean[] vis = new boolean[g.length];
      deque.addFirst(0);
      vis[0] = true;
      while (!deque.isEmpty()) {
        int v = deque.peekFirst();
        for (int u : g[v]) {
          if (vis[u]) continue;
          graph.get(v).add(new WeightedLCA.Edge(u, U[v]));
          graph.get(u).add(new WeightedLCA.Edge(v, U[v]));
          vis[u] = true;
          deque.addFirst(u);
        }
        if (deque.peekFirst() == v) deque.pollFirst();
      }
    }

  }

  static class WeightedLCA {
    static class Edge {
      long weight;
      int to;
      Edge(int to, long weight) {
        this.to = to;
        this.weight = weight;
      }
    }

    ArrayList<ArrayList<Edge>> G;
    int[][] parent;
    int[] depth;
    long[] dist;
    int root, logV;

    void build(int root) {
      Arrays.fill(depth, -1);
      ArrayDeque<Integer> stack = new ArrayDeque<>();
      stack.addFirst(root);
      parent[0][root] = -1;
      depth[root] = 0;
      dist[root] = 0;
      while (!stack.isEmpty()) {
        int v = stack.peekFirst();
        for (Edge e : G.get(v)) {
          int u = e.to;
          if (depth[u] >= 0) continue;
          parent[0][u] = v;
          depth[u] = depth[v] + 1;
          dist[u] = dist[v] + e.weight;
          stack.addFirst(u);
        }
        if (stack.peekFirst() == v) stack.pollFirst();
      }
    }

    WeightedLCA(final ArrayList<ArrayList<Edge>> adj) {
      int V = adj.size();
      root = 0;
      G = adj;
      dist = new long[V];
      depth = new int[V];

      logV = 1;
      for (int i = 1; i <= V; ) {
        i *= 2;
        logV++;
      }
      parent = new int[logV][V];

      build(root);

      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]];
          }
    }

    int getLCA(int u, int v) {
      if (depth[u] > depth[v]) {
        int tu = u;
        u = v;
        v = tu;
      }
      for (int k = 0; k < logV; ++k) if (((depth[v] - depth[u]) >> k & 1) != 0) 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];
    }

    long getLength(int u, int v) {
      int lca = getLCA(u, v);
      return dist[u] + dist[v] - dist[lca] * 2;
    }
  }

  // Template
  public static void main(String[] args) {
    OutputStream outputStream = System.out;
    FastScanner in = new FastScanner();
    PrintWriter out = new PrintWriter(outputStream);
    Task solver = new Task();
    solver.solve(in, out);
    out.close();
  }
  private static class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int bufferLength = 0;

    private boolean hasNextByte() {
      if (ptr < bufferLength) {
        return true;
      } else {
        ptr = 0;
        try {
          bufferLength = in.read(buffer);
        } catch (IOException e) {
          e.printStackTrace();
        }
        if (bufferLength <= 0) {
          return false;
        }
      }
      return true;
    }

    private int readByte() {
      if (hasNextByte()) return buffer[ptr++];
      else return -1;
    }

    private static boolean isPrintableChar(int c) {
      return 33 <= c && c <= 126;
    }

    private void skipUnprintable() {
      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
    }

    boolean hasNext() {
      skipUnprintable();
      return hasNextByte();
    }

    public String next() {
      if (!hasNext()) throw new NoSuchElementException();
      StringBuilder sb = new StringBuilder();
      int b = readByte();
      while (isPrintableChar(b)) {
        sb.appendCodePoint(b);
        b = readByte();
      }
      return sb.toString();
    }

    long nextLong() {
      if (!hasNext()) throw new NoSuchElementException();
      long n = 0;
      boolean minus = false;
      int b = readByte();
      if (b == '-') {
        minus = true;
        b = readByte();
      }
      if (b < '0' || '9' < b) {
        throw new NumberFormatException();
      }
      while (true) {
        if ('0' <= b && b <= '9') {
          n *= 10;
          n += b - '0';
        } else if (b == -1 || !isPrintableChar(b)) {
          return minus ? -n : n;
        } else {
          throw new NumberFormatException();
        }
        b = readByte();
      }
    }

    double nextDouble() {
      return Double.parseDouble(next());
    }

    double[] nextDoubleArray(int n) {
      double[] array = new double[n];
      for (int i = 0; i < n; i++) {
        array[i] = nextDouble();
      }
      return array;
    }

    double[][] nextDoubleMap(int n, int m) {
      double[][] map = new double[n][];
      for (int i = 0; i < n; i++) {
        map[i] = nextDoubleArray(m);
      }
      return map;
    }

    public int nextInt() {
      return (int) nextLong();
    }

    public int[] nextIntArray(int n) {
      int[] array = new int[n];
      for (int i = 0; i < n; i++) {
        array[i] = nextInt();
      }
      return array;
    }
  }
}