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#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(int i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{
    long long start_, end_, step_;
   public:
    struct range_iterator{
      long long val, step_;
      range_iterator(long long v, long long step) : val(v), step_(step) {}
      long long operator * (){return val;}
      void operator ++ (){val += step_;}
      bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;}
    };
    range(long long len) : start_(0), end_(len), step_(1) {}
    range(long long start, long long end) : start_(start), end_(end), step_(1) {}
    range(long long start, long long end, long long step) : start_(start), end_(end), step_(step) {}
    range_iterator begin(){ return range_iterator(start_, step_); }
    range_iterator   end(){ return range_iterator(  end_, step_); }
  };

  string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){
    stringstream ss; for(int i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str();
  }

  string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }

}

constexpr long long mod = 9_ten + 7;
//HL分解 構築O(|v|), 空間O(|v|)
class HeavyLightDecomposition{
 public:
  struct heavy_set{
    vector<int> element;
    int depth;
    int parent_vertex;
    heavy_set(int v, int d, int par) : element(1,v), depth(d), parent_vertex(par){}
  };

  vector<vector<int>>& G;
  vector<heavy_set> S;
  vector<int> subtree_size;
  vector<int> set_index;
  vector<int> ele_index;

 private:
  int get_subtree_size(int pos, int par){
    int sz = 1;
    for(int ch : G[pos]){
      if(ch == par) continue;
      sz += get_subtree_size(ch, pos);
    }
    return subtree_size[pos] = sz;
  }

  void make_path(int pos, int par, int set_id){
    set_index[pos] = set_id;
    ele_index[pos] = S[set_id].element.size()-1;

    int largest_child = -1;
    int value = 0;

    for(int ch : G[pos]){
      if(ch == par) continue;
      if(value < subtree_size[ch]){
        value = subtree_size[ch];
        largest_child = ch;
      }
    }

    for(int ch : G[pos]){
      if(ch == par) continue;
      if(largest_child == ch){
        S[set_id].element.push_back(ch);
        make_path(ch, pos, set_id);
      }else{
        S.emplace_back( ch, S[set_id].depth+1, pos );
        make_path(ch, pos, S.size()-1);
      }
    }
  }

  void init(int root){
    subtree_size.resize(G.size(), 0);
    get_subtree_size(root,root);

    set_index.resize(G.size(), 0);
    ele_index.resize(G.size(), 0);

    S.emplace_back( root,0,root );

    make_path( root, root, 0 );

    subtree_size.clear();
  }

 public:
  HeavyLightDecomposition(vector<vector<int>>& G_, int root = 0) : G(G_){
    init(root);
  }

  //set_index, element_index
  //S[set_index].element[element_index] == v
  pair<int,int> get_position(int v){
    return {set_index[v], ele_index[v]};
  }
};

//Lowest Common Ancestor with HL-decomposition tree
//O(log n) / query
int LCA(HeavyLightDecomposition& T, int u, int v){
  auto pu = T.get_position(u);
  auto pv = T.get_position(v);
  if(pu.first == pv.first){
    return pu.second < pv.second ? u : v;
  }

  if(T.S[pu.first].depth > T.S[pv.first].depth){
    swap(pu, pv);
    swap(u,v);
  }

  while(T.S[pu.first].depth != T.S[pv.first].depth){
    v = T.S[pv.first].parent_vertex;
    pv = T.get_position( v );
  }

  while(pu.first != pv.first){
    u = T.S[pu.first].parent_vertex;
    v = T.S[pv.first].parent_vertex;
    pu = T.get_position(u);
    pv = T.get_position(v);
    if(T.S[pv.first].depth == 0) break;
    if(T.S[pv.first].depth == 0) break;
  }

  if(pu.first == pv.first){
    return pu.second < pv.second ? u : v;
  }else{
    abort();
  }
  return -1;
}


void Euler_tour(vector<vector<int>>& G, int pos, int last, vector<int>& res){
  res.push_back(pos);
  for(int nx : G[pos]){
    if(nx == last) continue;
    Euler_tour(G, nx, pos, res);
  }
  res.push_back(pos);
}

int main(){
  int n;
  cin >> n;
  vector<vector<int>> G(n);
  for(int i :range(n-1)){
    int a,b;
    cin >> a,b;
    G[a].push_back(b);
    G[b].push_back(a);
  }


  vector<int> u(n);
  cin >> u;

  HeavyLightDecomposition t(G, 0);
  vector<int> e;
  Euler_tour(G, 0, 0, e);
  vector<int> o(n, 1e8);
  vector<int> s(e.size(),  0);
  for(int i=0; i<e.size(); i++){
    o[e[i]] = min(o[e[i]], i);
    if( o[e[i]] == i){
      s[i] = +u[e[i]];
    }else{
      s[i] = -u[e[i]];
    }
  }

  for(int i=1; i<s.size(); i++){
    s[i] += s[i-1];
  }

  long long ans = 0;
  int m;
  cin >> m;
  while(m--){
    int a,b,c;
    cin >> a,b,c;

    int p = o[LCA(t, a,b)];
    int w = o[a];
    int v = o[b];

    if(w>v) swap(w,v);

    long long tmp = 0;
    tmp += s[w] - (p==0 ? 0 : s[p-1]);
    tmp += s[v] - s[p];
    ans += tmp * c;
  }

  println(ans);
  return 0;
}