#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
struct fenwick_tree {
long long fenw[N];
fenwick_tree() {
memset(fenw, 0, sizeof(fenw));
}
void reset() {
memset(fenw, 0, sizeof(fenw));
}
void upd(int idx, int val) {
for (; idx < N; idx |= (idx + 1)) {
fenw[idx] += val;
}
}
long long get(int idx) {
long long res = 0;
for (; idx >= 0; idx &= (idx + 1), --idx) {
res += fenw[idx];
}
return res;
}
long long get(int l, int r) {
return get(r) - get(l - 1);
}
};
int n, m, q;
int a[N], b[N];
int p[N], c[N];
int ord[N];
int s[N], t[N], x[N];
long long y[N];
int l[N], r[N], ans[N];
vector<int> cand[N];
vector<pair<int, int>> g[N];
int dep[N], sz[N], son[N], fa[N], head[N], pos[N];
int hld_timer = 0;
fenwick_tree gold, silver;
void dfs(int u, int p, int d, int pid) {
sz[u] = 1;
fa[u] = p;
dep[u] = d;
int mx = 0;
for (pair<int, int> &e : g[u]) {
int v, id;
tie(v, id) = e;
if (id == pid) {
continue;
}
dfs(v, u, d + 1, id);
sz[u] += sz[v];
if (sz[v] > mx) {
mx = sz[v];
son[u] = v;
}
}
}
void decompose(int u, int p, int h) {
head[u] = h;
pos[u] = ++hld_timer;
if (son[u] != 0) {
decompose(son[u], u, h);
}
for (pair<int, int> &e : g[u]) {
int v, id;
tie(v, id) = e;
if (v == p || v == son[u]) {
continue;
}
decompose(v, u, v);
}
}
void silver_upd(int i, int w) {
int u = dep[a[i]] > dep[b[i]] ? a[i] : b[i];
silver.upd(pos[u], w);
}
void gold_upd(int i, int w) {
int u = dep[a[i]] > dep[b[i]] ? a[i] : b[i];
gold.upd(pos[u], w);
}
int gold_que(int u, int v) {
int sum = 0;
while (head[u] != head[v]) {
if (dep[head[u]] > dep[head[v]]) {
swap(u, v);
}
sum += gold.get(pos[head[v]], pos[v]);
v = fa[head[v]];
}
if (dep[u] > dep[v]) {
swap(u, v);
}
if (pos[u] < pos[v]) {
sum += gold.get(pos[u] + 1, pos[v]);
}
return sum;
}
long long silver_que(int u, int v) {
long long sum = 0;
while (head[u] != head[v]) {
if (dep[head[u]] > dep[head[v]]) {
swap(u, v);
}
sum += silver.get(pos[head[v]], pos[v]);
v = fa[head[v]];
}
if (dep[u] > dep[v]) {
swap(u, v);
}
if (pos[u] < pos[v]) {
sum += silver.get(pos[u] + 1, pos[v]);
}
return sum;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> q;
for (int i = 1; i <= n - 1; i++) {
cin >> a[i] >> b[i];
g[a[i]].emplace_back(b[i], i);
g[b[i]].emplace_back(a[i], i);
}
dfs(1, 1, 0, 0);
decompose(1, 1, 1);
for (int i = 1; i <= m; i++) {
cin >> p[i] >> c[i];
}
iota(ord + 1, ord + m + 1, 1);
sort(ord + 1, ord + m + 1, [](const int &u, const int &v) -> bool {
return c[u] < c[v];
});
for (int i = 1; i <= q; i++) {
cin >> s[i] >> t[i] >> x[i] >> y[i];
l[i] = 1;
r[i] = m + 1;
ans[i] = -1;
}
for (int ite = 1; ite <= 20; ite++) {
silver.reset();
gold.reset();
for (int i = 1; i <= m; i++) {
silver_upd(p[i], c[i]);
}
for (int i = 1; i <= m + 1; i++) {
cand[i].clear();
}
for (int i = 1; i <= q; i++) {
if (l[i] > r[i]) {
continue;
}
cand[l[i] + r[i] >> 1].emplace_back(i);
}
for (int i = m + 1; i >= 1; i--) {
if (i != m + 1) {
silver_upd(p[ord[i]], -c[ord[i]]);
gold_upd(p[ord[i]], +1);
}
for (int &idx : cand[i]) {
if (silver_que(s[idx], t[idx]) <= y[idx]) {
if (gold_que(s[idx], t[idx]) <= x[idx]) {
ans[idx] = x[idx] - gold_que(s[idx], t[idx]);
}
l[idx] = i + 1;
} else {
r[idx] = i - 1;
}
}
}
}
for (int i = 1; i <= q; i++) {
cout << ans[i] << '\n';
}
return 0;
}
