#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <stack>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

int N;
vector<int> G[100005];
int parent[64][100005];
int depth[100005];

int dp[100005];
int weight[100005];

void dfs(int v, int p, int d){
  parent[0][v] = p;
  depth[v] = d;
  dp[v] = (p!=-1?dp[p]:0) + weight[v];
  for(int i=0; i<G[v].size(); i++){
    if(G[v][i] != p) dfs(G[v][i], v, d+1);
  }
}
void init(int root){
  dfs(root, -1, 0);
  for(int k=0; k+1<64; k++){
    for(int v=0; v<N+1; v++){
      if(parent[k][v] < 0) parent[k+1][v] = -1;
      else parent[k+1][v] = parent[k][parent[k][v]];
    }
  }
}
int lca(int u, int v){
  if(depth[u] > depth[v]) swap(u, v);
  for(int k=0; k<64; k++){
    if((depth[v] - depth[u]) >> k & 1){
      v = parent[k][v];
    }
  }
  if(u==v) return u;
  for(int k=64-1; k>=0; k--){
    if(parent[k][u] != parent[k][v]){
      u = parent[k][u];
      v = parent[k][v];
    }
  }
  return parent[0][u];
}


int main(){
  ios::sync_with_stdio(false);
  cin >> N;
  rep(i,N-1){
    int a, b;
    cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  rep(i,N){
    cin >> weight[i];
  }
  dp[0] = weight[0];
  init(0);
  
  int M;
  cin >> M;
  
  ll ret = 0;
  rep(i,M){
    int a, b, c;
    cin >> a >> b >> c;
    int l = lca(a, b);
    //cout << " " << dp[a] << " " << dp[b] << " " << dp[l] << " " << weight[l] << endl;
    ret += (dp[a] + dp[b] - 2LL*dp[l] + weight[l]) * (ll)c;
  }
  cout << ret << endl;
  
  return 0;
}