#include <bits/stdc++.h>
#define EPS 1e-9
#define INF 1070000000LL
#define MOD 1000000007LL
#define fir first
#define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++)
#define numa(x,a) for(auto x: a)
#define ite iterator
#define mp make_pair
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define pb push_back
#define pf push_front
#define sec second
#define sz(x) ((int)(x).size())
#define ALL( c ) (c).begin(), (c).end()
#define gcd(a,b) __gcd(a,b)
#define mem(x,n) memset(x,n,sizeof(x))
#define endl "\n"
using namespace std;
template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}
template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }
template <class T,class U> std::ostream& operator<<(std::ostream &os, std::pair<T,U> &p){ os << "(" << p.first <<", " << p.second <<")";return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }
#define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; }
#define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); }
#define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); }
#define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); }
using ll = long long;

int U[100100];

template <int MAX_V = 100100, int MAX_LOG_V = 18>
class LCA{
  int root;
  vector <int> edge[MAX_V];
  int parent[MAX_LOG_V][MAX_V];
  int depth[MAX_V];
  int cost[MAX_V];
  int V;
public:
 
  LCA(){
    root = 0;
    V = MAX_V;
  }
  inline void dfs(int v,int p,int d){
    parent[0][v] = p;
    depth[v] = d;
    for(int i = 0;i < sz(edge[v]);i++){
      if(edge[v][i] != p){
        dfs(edge[v][i],v,d+1);
      }
    }
  }
  inline void add_edge(int x,int y) {
    edge[x].pb(y);
    edge[y].pb(x);
  }
  inline void init(int root_, int V_){
    root = root_; V = V_;
    //parent[0]とrootを初期化
    dfs(root,-1,0);
    //parentを初期化する
    for(int k = 0;k+1<MAX_LOG_V;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]];
        }
      }
    }
    dfs2(root);
  }

  inline int query(int u,int v){
    if(depth[u] > depth[v]){
      swap(u,v);
    }
    for(int k = 0; k < MAX_LOG_V;k++){
      if((depth[v]-depth[u]) >> k & 1){
        v = parent[k][v];
      }
    }
    if(u == v){
      return u;
    }
    for(int k = MAX_LOG_V-1;k >= 0;k--){
      if(parent[k][u] != parent[k][v]){
        u = parent[k][u];
        v = parent[k][v];
      }
    }
    return parent[0][u];
  }

  void dfs2(int v, int par = -1, int c = 0){
    int nc = c + U[v];
    cost[v] = nc;
    numa(x, edge[v]){
      if (x == par) continue;
      dfs2(x, v, nc);
    }
  }
  ll solve(int u, int v){
    int par = query(u,v);
    return cost[u] + cost[v] - cost[par] * 2 + U[par];
  }
};
LCA<100010, 17> lca;

int main()
{
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  int N;
  cin >> N;
  rep(i,N-1){
    int u,v;
    cin >> u >> v;
    lca.add_edge(u, v);
  }

  rep(i,N){
    cin >> U[i];
  }
  lca.init(0, N);
  int M;
  cin >> M;
  ll ans = 0;
  rep(i,M){
    int u,v,c;
    cin >> u >> v >> c;
    ans += lca.solve(u, v) * c;
  }
  cout << ans << endl;
  return 0;
}