#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 100100;
const int L = 18;
int n, m, a[N], b[N], c[N], dep[N], in[N], out[N], dp[N], sum[N], t[N * 4], par[N][L], timer = 0;
vector<int> adj[N], que[N];
void upd (int id, int l, int r, int k, int x){
if (k > r){
return;
}
if (l == r){
t[id] += x;
return;
}
int m = l + r >> 1;
if (k <= m){
upd(id * 2, l, m, k, x);
} else {
upd(id * 2 + 1, m + 1, r, k, x);
}
t[id] = t[id * 2] + t[id * 2 + 1];
return;
}
int get (int id, int l, int r, int u, int v){
if (l > v || r < u){
return 0;
}
if (l >= u && r <= v){
return t[id];
}
int m = l + r >> 1;
return get(id * 2, l, m, u, v) + get(id * 2 + 1, m + 1, r, u, v);
}
void dfs (int u, int p = 0){
dep[u] = dep[p] + 1;
in[u] = out[u] = ++timer;
par[u][0] = p;
for (int i = 1; i < L; ++i){
par[u][i] = par[par[u][i - 1]][i - 1];
}
for (int v : adj[u]){
if (v != p){
dfs(v, u);
}
}
out[u] = timer;
return;
}
int lft (int u, int x){
for (int i = 0; i < L; ++i){
if (x & (1 << i)){
u = par[u][i];
}
}
return u;
}
int lca (int u, int v){
if (dep[u] < dep[v]){
swap(u, v);
}
u = lft(u, dep[u] - dep[v]);
if (u == v){
return u;
}
for (int i = L - 1; i >= 0; --i){
if (par[u][i] != par[v][i]){
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void upd (int u, int x){
upd(1, 1, n, in[u], x);
upd(1, 1, n, out[u] + 1, -x);
return;
}
int get (int u){
return get(1, 1, n, 1, in[u]);
}
void sol (int u, int p = 0){
for (int v : adj[u]){
if (v != p){
sol(v, u);
dp[u] = max(dp[u], dp[v]);
sum[u] += dp[v];
}
}
dp[u] = max(dp[u], sum[u]);
upd(u, sum[u]);
for (int i : que[u]){
int road = get(a[i]) + get(b[i]) - 2ll * get(u) + sum[u];
dp[u] = max(dp[u], road + c[i]);
}
upd(u, -dp[u]);
return;
}
int32_t main (){
ios::sync_with_stdio(false); cin.tie(nullptr);
if (fopen ("test.inp", "r")){
freopen ("test.inp", "r", stdin);
freopen ("test.out", "w", stdout);
}
cin >> n;
for (int i = 1; i < n; ++i){
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1);
cin >> m;
for (int i = 1; i <= m; ++i){
cin >> a[i] >> b[i] >> c[i];
que[lca(a[i], b[i])].push_back(i);
}
sol(1);
cout << max(0ll, *max_element(dp, dp + N)) << "\n";
}
