#include <bits/stdc++.h>
using namespace std;
namespace std {
#ifndef LOCAL
#define cerr \
if (0) cerr
#endif
} // namespace std
template <class T>
struct FT {
vector<T> ft;
FT(int _n = 0) {
ft.assign(_n + 5, 0);
}
void upd(int id, T val) {
for (; id < (int)ft.size(); id += id & -id) ft[id] += val;
}
T get(int id) {
T ans = 0;
for (; id > 0; id -= id & -id) ans += ft[id];
return ans;
}
};
const int N = 1e5 + 5;
int n, m, q;
pair<int, int> e[N];
vector<int> g[N];
int lc[N];
pair<int, int> mark[N];
array<int64_t, 4> qr[N];
int f[N][20];
int h[N];
int tin[N];
int tout[N];
int time_dfs;
int ans[N];
int lo[N], hi[N];
vector<int> rem[N];
void dfs(int u) {
tin[u] = ++time_dfs;
for (int i = 0; f[f[u][i]][i]; i++) {
f[u][i + 1] = f[f[u][i]][i];
}
for (int v : g[u]) {
if (v == f[u][0]) {
continue;
}
f[v][0] = u;
h[v] = h[u] + 1;
dfs(v);
}
tout[u] = time_dfs;
}
void init() {
h[1] = 1;
dfs(1);
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
while (h[u] > h[v]) {
u = f[u][__lg(h[u] - h[v])];
}
if (u == v) {
return u;
}
for (int i = __lg(h[u]); i >= 0; i--) {
if (f[u][i] != f[v][i]) {
u = f[u][i];
v = f[v][i];
}
}
return f[u][0];
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
#ifdef LOCAL
#define task "a"
#else
#define task ""
#endif
if (fopen(task ".inp", "r")) {
freopen(task ".inp", "r", stdin);
freopen(task ".out", "w", stdout);
}
cin >> n >> m >> q;
for (int i = 1; i < n; i++) {
auto& [u, v] = e[i];
cin >> u >> v;
g[u].emplace_back(v);
g[v].emplace_back(u);
}
for (int i = 1; i <= m; i++) {
cin >> mark[i].second >> mark[i].first;
}
init();
for (int i = 1; i < n; i++) {
auto& [u, v] = e[i];
if (h[u] > h[v]) swap(u, v);
}
sort(mark + 1, mark + 1 + m, greater<pair<int, int>>());
for (int i = 1; i <= q; i++) {
for (int j = 0; j < 4; j++) {
cin >> qr[i][j];
}
lc[i] = lca(qr[i][0], qr[i][1]);
lo[i] = 0, hi[i] = m;
ans[i] = qr[i][2] + 1;
}
while (true) {
for (int i = 0; i <= m; i++) {
rem[i].clear();
}
int sus = 0;
for (int i = 1; i <= q; i++) {
if (lo[i] <= hi[i]) {
sus = 1;
rem[(lo[i] + hi[i]) >> 1].push_back(i);
}
}
if (!sus) break;
FT<int64_t> ft_sum(n);
FT<int> ft_cnt(n);
for (int i = 1; i <= m; i++) {
auto [w, id] = mark[i];
auto [u, v] = e[id];
ft_sum.upd(tin[v], w);
ft_sum.upd(tout[v] + 1, -w);
}
// used i largest marked edges
for (int i = 0; i <= m; i++) {
if (i) {
auto [w, id] = mark[i];
auto [u, v] = e[id];
ft_sum.upd(tin[v], -w);
ft_sum.upd(tout[v] + 1, +w);
ft_cnt.upd(tin[v], 1);
ft_cnt.upd(tout[v] + 1, -1);
}
for (int que : rem[i]) {
int u = qr[que][0];
int v = qr[que][1];
int lca = lc[que];
int64_t used_silver = ft_sum.get(tin[u]) + ft_sum.get(tin[v]) - 2 * ft_sum.get(tin[lca]);
int used_gold = ft_cnt.get(tin[u]) + ft_cnt.get(tin[v]) - 2 * ft_cnt.get(tin[lca]);
if (used_silver <= qr[que][3]) {
ans[que] = used_gold;
hi[que] = i - 1;
} else {
lo[que] = i + 1;
}
}
}
}
for (int i = 1; i <= q; i++) {
cout << max<int64_t>(-1, qr[i][2] - ans[i]) << "\n";
}
return 0;
}
