#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const ll MOD = 1e9 + 7;
const ll infmax = ~(1LL << 64 - 1) / 10;
const ll infmin = (1LL << 64 - 1) / 10;
const ll maxq = 1e5 + 5, maxn = 1e5 + 5;
struct Query {
ll id, s, t, x, y;
};
vector<pair<ll, ll>> adj[maxn];
vector<ll> checkpolls[maxn];
vector<Query> queries;
ll n, m, q;
ll res[maxq];
ll childSz[maxn];
bool removed[maxn];
vector<ll> compNode;
vector<ll> pathCost[maxn], pathpSum[maxn];
ll subPar[maxn];
void getCompNode(ll u, ll p) {
compNode.push_back(u);
for(auto &[v, w]: adj[u]) {
if(v != p && !removed[v]) {
getCompNode(v, u);
}
}
}
void dfsSz(ll u, ll p) {
childSz[u] = 1;
for(auto &[v, w]: adj[u]) {
if(v != p && !removed[v]) {
dfsSz(v, u);
childSz[u] += childSz[v];
}
}
}
ll findCentroid(ll u, ll p, ll totalSz) {
for(auto &[v, w]: adj[u]) {
if(v != p && !removed[v] && childSz[v] * 2 > totalSz) {
return findCentroid(v, u, totalSz);
}
}
return u;
}
void getPathInfo(ll u, ll p, ll c, ll rt) {
subPar[u] = rt;
for(auto &[v, idx]: adj[u]) {
if(v != p && !removed[v]) {
pathCost[v] = pathCost[u];
vector<ll> merged(pathCost[v].size() + checkpolls[idx].size());
merge(pathCost[v].begin(), pathCost[v].end(), checkpolls[idx].begin(), checkpolls[idx].end(), merged.begin());
pathCost[v] = merged;
pathpSum[v].assign(pathCost[v].size() + 1, 0);
for(ll i = 0; i < pathCost[v].size(); i++) {
pathpSum[v][i + 1] = pathpSum[v][i] + pathCost[v][i];
}
getPathInfo(v, u, c, rt);
}
}
}
ll calc(ll s, ll t, ll kSliver) {
auto& costS = pathCost[s];
auto& costT = pathCost[t];
auto& pss = pathpSum[s];
auto& pst = pathpSum[t];
if(kSliver > costS.size() + costT.size()) return infmax;
ll res = infmax;
for(ll i = 0; i <= costS.size(); i++) {
ll j = kSliver - i;
if(j >= 0 && j <= costT.size()) {
res = min(res, pss[i] + pst[j]);
}
}
return res;
}
void solve(ll entry, vector<Query>& queries, ll midGold, vector<bool>& ress) {
if(queries.empty()) return;
compNode.clear();
getCompNode(entry, 0);
ll totalSz = compNode.size();
dfsSz(entry, 0);
ll centroid = findCentroid(entry, 0, totalSz);
pathCost[centroid].clear();
pathpSum[centroid].assign(1, 0);
subPar[centroid] = centroid;
for(auto &[v, idx]: adj[centroid]) {
if(!removed[v]) {
pathCost[v] = checkpolls[idx];
pathpSum[v].assign(pathCost[v].size() + 1, 0);
for(ll i = 0; i < pathCost[v].size(); i++) {
pathpSum[v][i + 1] = pathpSum[v][i] + pathCost[v][i];
}
getPathInfo(v, centroid, centroid, v);
}
}
map<ll, vector<Query>> subQueries;
vector<Query> crossQ;
for(auto &q: queries) {
if(subPar[q.s] == subPar[q.t]) {
if(subPar[q.s] != centroid) {
subQueries[subPar[q.s]].push_back(q);
} else crossQ.push_back(q);
} else crossQ.push_back(q);
}
for(auto &q: crossQ) {
ll s = q.s, t = q.t;
ll pcheckpolls = pathCost[s].size() + pathCost[t].size();
ll kSliver = pcheckpolls - midGold;
bool flag = false;
if(kSliver < 0) flag = true;
else {
ll sliver = calc(s, t, kSliver);
if(sliver < q.y) {
flag = true;
}
}
ress[q.id] = flag;
}
removed[centroid] = true;
for(auto &[rt, qs]: subQueries) {
solve(rt, qs, midGold, ress);
}
}
void pbs(vector<Query> queries, ll mingold, ll maxgold) {
if (queries.empty() || mingold > maxgold) {
return;
}
ll midgold = mingold + (maxgold - mingold) / 2;
vector<Query> possibleqs, impossibleqs;
fill(removed + 1, removed + n + 1, false);
vector<bool> results(q);
solve(1, queries, midgold, results);
for (const auto& q : queries) {
if (results[q.id]) {
res[q.id] = midgold;
possibleqs.push_back(q);
} else {
impossibleqs.push_back(q);
}
}
pbs(possibleqs, mingold, midgold - 1);
pbs(impossibleqs, midgold + 1, maxgold);
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> n >> m >> q;
for (ll i = 1; i < n; ++i) {
ll u, v;
cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
for (ll i = 0; i < m; ++i) {
ll p, c; cin >> p >> c;
checkpolls[p].push_back(c);
}
for (ll i = 1; i < n; ++i) sort(checkpolls[i].begin(), checkpolls[i].end());
for (ll i = 0; i < q; ++i) {
ll s, t, x, y; cin >> s >> t >> x >> y;
queries.push_back({i, s, t, x, y});
}
fill(res, res + q, -1);
pbs(queries, 0, n);
for (ll i = 0; i < q; ++i) {
ll gold = res[i];
if (gold != -1 && queries[i].x >= gold) {
cout << queries[i].x - gold << "\n";
} else {
cout << -1 << "\n";
}
}
return 0;
}
