#include "bits/stdc++.h"
using namespace std;
#define int long long
#define FOR(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--)
#define ALL(a) (a).begin(),(a).end()
#define UNIQUE_SORT(l) sort(ALL(l)); l.erase(unique(ALL(l)), l.end());
#define CONTAIN(a, b) find(ALL(a), (b)) != (a).end()
#define array2(type, x, y) array<array<type, y>, x>
#define vector2(type) vector<vector<type> >
#define out(...) printf(__VA_ARGS__)

int dxy[] = {0, 1, 0, -1, 0};

void solve();
signed main()
{
#if DEBUG
    std::ifstream in("input.txt");
    std::cin.rdbuf(in.rdbuf());
#endif
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
    return 0;
}

/*================================*/

int N,M,Q;

/**********************************
 *
 * Graph
 *
 **********************************/

struct Edge {
    int src, to, w;
    Edge(int u, int v, int w): src(u), to(v), w(w) {};
};

vector< vector<Edge> > E(111111);
int W[111111];
int U[111111];
int D[111111];
int P[111111][20];

void doubling() {
    FOR(j, 1, 20) {
        REP(i, N) {
            P[i][j] = (P[i][j-1] == -1) ? -1 : P[P[i][j-1]][j-1];
        }
    }
}

void add_edge(int u, int v, int w) {
    E[u].push_back(*new Edge(u,v,w));
    E[v].push_back(*new Edge(v,u,w));
}

void dfs(int parent=-1, int i=0, int weight=0, int depth=0) {
    P[i][0] = parent;
    W[i] = weight+U[i];
//    out("%lld: %lld -> %lld\n", i, U[i], W[i]);
    D[i] = depth;
    for (auto e : E[i]) {
        if (e.to == parent) continue;
        dfs(i, e.to, W[i], depth+1);
    }
}

int lca(int u, int v) {
    // depth調整
    if (D[u] > D[v]) swap(u, v);
    RFOR(i, 0, 20) {
        if ((D[v] - D[u])&(1<<i)) v = P[v][i];
    }
    if (u == v) return u;
    
    // lca
    RFOR(i, 0, 20) {
        if (P[v][i] != P[u][i]) {
            v = P[v][i];
            u = P[u][i];
        }
    }
    return P[u][0];
}

int route_weight(int u, int v) {
    return W[u] + W[v] - W[lca(u, v)] * 2;
}

void setup_tree() {
    REP(i,N)REP(j,20) P[i][j]=-1;
    dfs();
    doubling();
}
/**********************************************************/


void solve() {
    cin>>N;
    
    int a,b,c;
    REP(i,N-1) {
        cin>>a>>b;
        add_edge(a, b, 0);
    }
    REP(i,N) cin>>U[i];
    setup_tree();
    
    cin >> M;
    int ans = 0;
    REP(i,M) {
        cin>>a>>b>>c;
        int l = lca(a,b);
        ans += (W[a]+W[b]-2*W[l]+U[l])*c;
    }
    
    cout << ans << endl;
}