#include <bits/stdc++.h>
#define pw2(i) (1LL << (i))
#define all(v) (v).begin(), (v).end()
using namespace std;
using ll = long long;
/*------------- I alone decide my fate ! -------------*/
/*------ We wish you a Merry Christmas and a happy new year! ------*/
int N, M, Q, res[100009];
struct query {
int s, t, x;
ll y;
} q[100009];
pair <int, int> edge[1000009], tram[100009];
vector <int> adj[100009];
int tin[100009], tout[100009], timeDFS = 0;
int lef[100009], righ[100009], up[100009][18], dep[100009], lca[100009];
vector <int> inQ[100009];
void DFS(int u, int p) {
tin[u] = ++timeDFS;
for (auto v : adj[u]) {
if (v == p) continue;
up[v][0] = u;
dep[v] = dep[u] + 1;
for (int i = 1; i <= 17; i ++) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
DFS(v, u);
}
tout[u] = timeDFS;
}
int getlca(int a, int b) {
if (dep[a] < dep[b]) swap(a, b);
int len = dep[a] - dep[b];
for (int i = 0; i <= 17; i ++) {
if ((len >> i) & 1) {
a =up[a][i];
}
}
if (a == b) return a;
for (int i = 17; i >= 0; i --) {
if (up[a][i] != up[b][i]) {
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
}
struct Fenwick{
int n;
vector <ll> bit;
vector <pair <int, int> > undo;
void init(int _n) {
n = _n;
bit.resize(n + 9, 0);
}
void update(int x, int val, bool keep) {
if (keep) undo.push_back({x, -val});
while (x <= n) {
bit[x] += val;
x += x &- x;
}
}
ll get(int x) {
ll ret = 0;
while (x) {
ret += bit[x];
x -= x &- x;
}
return ret;
}
void reset() {
while (!undo.empty()) {
update(undo.back().first, undo.back().second, 0);
undo.pop_back();
}
}
} fenCnt, fenSum;
void solve() {
cin >> N >> M >> Q;
for (int i = 1; i < N; i ++) {
int u, v; cin >> u >> v;
edge[i] = {u, v};
adj[u].push_back(v);
adj[v].push_back(u);
}
for (int i = 1; i <= M; i ++) {
cin >> tram[i].first >> tram[i].second;
}
sort(tram + 1, tram + M + 1, [] (pair <int, int> a, pair <int, int> b) {
return a.second < b.second;
});
DFS(1, 0);
for (int i = 1; i <= M; i ++) {
int idx = tram[i].first;
if (tin[edge[idx].first] > tin[edge[idx].second]) {
swap(edge[idx].first, edge[idx].second);
}
}
for (int i = 1; i <= Q; i ++) {
lef[i] = 1; righ[i] = M;
cin >> q[i].s >> q[i].t >> q[i].x >> q[i].y;
lca[i] = getlca(q[i].s, q[i].t);
}
bool loop = 1;
fenCnt.init(N);
fenSum.init(N);
while (loop) {
loop = 0;
for (int i = 1; i <= Q; i ++) {
if (lef[i] > righ[i]) continue;
loop = 1;
int mid = (lef[i] + righ[i]) >> 1;
inQ[mid].push_back(i);
}
for (int i = 1; i <= M; i ++) {
int idx = tram[i].first;
int child = edge[idx].second;
fenCnt.update(tin[child], 1, 1);
fenCnt.update(tout[child] + 1, -1, 1);
fenSum.update(tin[child], tram[i].second, 1);
fenSum.update(tout[child] + 1, -tram[i].second, 1);
for (auto j : inQ[i]) {
int s = q[j].s, t = q[j].t;
int cnt = fenCnt.get(tin[s]) + fenCnt.get(tin[t]) - 2 * fenCnt.get(tin[lca[j]]);
ll sum = fenSum.get(tin[s]) + fenSum.get(tin[t]) - 2 * fenSum.get(tin[lca[j]]);
if (q[j].y >= sum) {
lef[j] = i + 1;
res[j] = cnt;
}
else righ[j] = i - 1;
}
inQ[i].clear();
}
fenCnt.reset(); fenSum.reset();
}
for (int i = 1; i <= M; ++i) {
int idx = tram[i].first;
int child = edge[idx].second;
fenCnt.update(tin[child], 1, 0);
fenCnt.update(tout[child] + 1, -1, 0);
}
vector<int> totalChk(Q+1);
for (int i = 1; i <= Q; ++i) {
int s = q[i].s, t = q[i].t, l = lca[i];
totalChk[i] = fenCnt.get(tin[s]) + fenCnt.get(tin[t]) - 2 * fenCnt.get(tin[l]);
}
for (int i = 1; i <= Q; ++i) {
int t = totalChk[i];
int s = res[i];
int goldNeeded = t - s;
if (goldNeeded > q[i].x) cout << -1 << '\n';
else cout << q[i].x - goldNeeded << '\n';
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
solve();
return 0;
}
/*
How can you see into my eyes, like open doors?
Leading you down into my core, where I've become so numb
Without a soul, my spirit's sleeping somewhere cold
Until you find it here and bring it back home!
Wake me up! Wake me up inside
Can't wake up? Wake me up inside
*/
