#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
const int inf = 1000000001;
const ll INF = 2e18 * 2;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };



struct Modint {
	ll n;
	static const ll Mod = 1000000007;
	Modint(int n = 0) : n(n) {}
};

Modint operator+(Modint a, Modint b) { return Modint((a.n += b.n) >= mod ? a.n - a.Mod : a.n); }
Modint operator-(Modint a, Modint b) { return Modint((a.n -= b.n) < 0 ? a.n + a.Mod : a.n); }
Modint operator*(Modint a, Modint b) { return Modint(1LL * a.n * b.n % a.Mod); }
Modint &operator+=(Modint &a, Modint b) { return a = a + b; }
Modint &operator-=(Modint &a, Modint b) { return a = a - b; }
Modint &operator*=(Modint &a, Modint b) { return a = a * b; }


struct HLDecomposition {
	int n, pos;
	vector<vector<int> > G;
	vector<int> vid, head, sub, hvy, par, dep, inv, type;

	HLDecomposition() {}
	HLDecomposition(int sz) :
		n(sz), pos(0), G(n),
		vid(n, -1), head(n), sub(n, 1), hvy(n, -1),
		par(n), dep(n), inv(n), type(n) {}

	void add_edge(int u, int v) {
		G[u].push_back(v);
		G[v].push_back(u);
	}

	void build(vector<int> rs = { 0 }) {
		int c = 0;
		for (int r : rs) {
			dfs(r);
			bfs(r, c++);
		}
	}

	void dfs(int rt) {
		using T = pair<int, int>;
		stack<T> st;
		par[rt] = -1;
		dep[rt] = 0;
		st.emplace(rt, 0);
		while (!st.empty()) {
			int v = st.top().first;
			int &i = st.top().second;
			if (i<(int)G[v].size()) {
				int u = G[v][i++];
				if (u == par[v]) continue;
				par[u] = v;
				dep[u] = dep[v] + 1;
				st.emplace(u, 0);
			}
			else {
				st.pop();
				int res = 0;
				for (int u : G[v]) {
					if (u == par[v]) continue;
					sub[v] += sub[u];
					if (res<sub[u]) res = sub[u], hvy[v] = u;
				}
			}
		}
	}

	void bfs(int r, int c) {
		int &k = pos;
		queue<int> q({ r });
		while (!q.empty()) {
			int h = q.front(); q.pop();
			for (int i = h; i != -1; i = hvy[i]) {
				type[i] = c;
				vid[i] = k++;
				inv[vid[i]] = i;
				head[i] = h;
				for (int j : G[i])
					if (j != par[i] && j != hvy[i]) q.push(j);
			}
		}
	}

	// for_each(vertex)
	// [l,r] <- attention!!
	void for_each(int u, int v, const function<void(int, int)>& f) {
		while (1) {
			if (vid[u]>vid[v]) swap(u, v);
			f(max(vid[head[v]], vid[u]), vid[v]);
			if (head[u] != head[v]) v = par[head[v]];
			else break;
		}
	}

	// for_each(edge)
	// [l,r] <- attention!!
	// 値が辺に乗っているときは、頂点から遠いほう(すなわちvidが大きいほう)の
	// 頂点に値を移す。yuki650
	void for_each_edge(int u, int v, const function<void(int, int)>& f) {
		while (1) {
			if (vid[u]>vid[v]) swap(u, v);
			if (head[u] != head[v]) {
				f(vid[head[v]], vid[v]);
				v = par[head[v]];
			}
			else {
				if (u != v) f(vid[u] + 1, vid[v]);
				break;
			}
		}
	}

	int lca(int u, int v) {
		while (1) {
			if (vid[u]>vid[v]) swap(u, v);
			if (head[u] == head[v]) return u;
			v = par[head[v]];
		}
	}

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

#define N 100010
vii G(N);
vl u(N);
vl sum(N);

void make_sum(int parent, int now) {
	if (now == 0) {
		sum[now] = u[now];
	}
	else {
		sum[now] = sum[parent] + u[now];
	}
	rep(i, G[now].size()) {
		if (G[now][i] == parent) {
			continue;
		}
		make_sum(now, G[now][i]);
	}
}


int main() {
	int n, i, j;
	cin >> n;
	HLDecomposition hld(n);
	vi a(n - 1), b(n - 1);
	rep(i, n - 1) {
		cin >> a[i] >> b[i];
		hld.add_edge(a[i], b[i]);
		G[a[i]].push_back(b[i]);
		G[b[i]].push_back(a[i]);
	}
	hld.build();
	u.resize(n);
	rep(i, n) {
		cin >> u[i];
	}
	//DEBUG_VEC(u);
	sum.resize(n);
	make_sum(-1, 0);
	//DEBUG_VEC(sum);
	int m;
	cin >> m;
	ll ans = 0;
	while (m--) {
		int a, b, c;
		cin >> a >> b >> c;
		int lca = hld.lca(a, b);
		int lcap = hld.par[lca];
		ll temp = sum[a] + sum[b] - sum[lca];
		if (lcap != -1) {
			temp -= sum[lcap];
		}
		ans += temp * c;
	}
	cout << ans << endl;

}