#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <queue>
#include "math.h"
#include <complex>
#include <iomanip>
#include <map>
#define ifor(i,a,b) for (int i=(a);i<(b);i++)
#define rfor(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define rep(i,n) for (int i=0;i<(n);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
using namespace std;
typedef long double ld;
typedef long long int  lli;
typedef complex <double> P;
const double eps = 1e-11;
int vex[4]={1,0,-1,0};
int vey[4]={0,1,0,-1};
typedef vector<double> Vec;
typedef vector<int> vec;
typedef vector<Vec> MAT;
typedef vector<vec> mat;
lli MOD=1000000007;
vector<int> E[100005];
int par[100005][20];
int depth[100005];

void dfs(int v,int p,int d)
{
  par[v][0]=p;
  depth[v]=d;
  for(int i=0;i<E[v].size();i++)
  {
    if(E[v][i]==p)continue;
    dfs(E[v][i],v,d+1);
  }
}
void search_depth(int root){
  dfs(root,-1,0); 
}
void fill_table(){
  rep(i,19){
    rep(j,100004){
      if(par[j][i] == -1)par[j][i+1] =-1;
      else par[j][i+1]= par[par[j][i]][i];
    }
  }

}
int lca(int u,int v)
{
  if(depth[u]>depth[v])swap(u,v);
  for(int i=19;i>=0;i--)
  {
    if(((depth[v]-depth[u])>>i)&1)v=par[v][i];
  }
  if(u==v)return u;
  for(int i=19;i>=0;i--)
  {
    if(par[u][i]!=par[v][i])
    {
      u = par[u][i];
      v = par[v][i];
    }
  }
  return par[u][0];
}

int main(){
  int N;
  cin >> N;
  int a,b,c;
  par[0][0]=-1;
  rep(i,N-1){
    cin>>a >>b;
    E[a].push_back(b);
    E[b].push_back(a);
  }

  queue<int> que;
  que.push(0);
  lli cost [100005],x[100005];
  rep(i,N)cin>>x[i];
  cost[0]= x[0];
  bool used[100005];
  while(!que.empty()){
    int t = que.front();que.pop();
    used[t]=true;
    rep(i,E[t].size()){
      int to = E[t][i];
      if(used[to])continue;
      cost[to] = cost[t]+x[to];
      que.push(to);
    }
  }
  search_depth(0);
  //rep(i,10)printf("(%d,%d)",i,depth[i]);
  fill_table();
  int M;
  cin >> M;
  lli ans =0; 
  rep(i,M){
    cin>>a>>b>>c;
    //cout<<lca(a,b)<<endl;
    int p = lca(a,b);
    //printf("%d %d %d\n",cost[a],cost[b],cost[p]);
    ans+= (cost[a]+cost[b]-2*cost[p]+x[p])*c;
  }
cout<<ans<<endl;
}