#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define ff first
#define ss second
#define all(a) (a).begin(), (a).end()
template<typename T>
int len(T &a){
return a.size();
}
void solve(){
int n, m, q; cin >> n >> m >> q;
vector<vector<pair<int,int>>> g(n);
for(int i = 0; i < n - 1; i ++){
int u, v; cin >> u >> v;
u --; v --;
g[u].push_back({v, i});
g[v].push_back({u, i});
}
vector<vector<int>> way(n - 1);
for(int i = 0; i < m; i ++){
int id, sil; cin >> id >> sil;
id --; way[id].push_back(sil);
}
vector<int> st(q), en(q), gold(q), silver(q);
for(int i = 0; i < q; i ++){
cin >> st[i] >> en[i] >> gold[i] >> silver[i];
st[i] --; en[i] --;
}
auto brute = [&]{
vector<int> par(n), wayid(n);
auto dfs = [&](auto &dfs, int i, int p = -1, int r = -1)->void{
par[i] = p;
wayid[i] = r;
for(auto [u, id] : g[i]){
if(u == p) continue;
dfs(dfs, u, i, id);
}
};
for(int i = 0; i < q; i ++){
dfs(dfs, st[i]);
vector<ll> pay;
int cur = en[i];
while(wayid[cur] != -1){
//cout << wayid[cur] + 1 << ' ';
for(auto u : way[wayid[cur]]){
pay.push_back(u);
//cout << u << ' ';
}
cur = par[cur];
}
sort(all(pay));
for(int j = 1; j < len(pay); j ++){
pay[j] += pay[j - 1];
}
int rem = gold[i] - len(pay) + (upper_bound(all(pay), silver[i]) - pay.begin());
cout << max(-1, rem) << '\n';
}
};
brute();
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
int testcases = 1;
#ifdef Tests
cin >> testcases;
#endif
while(testcases --){
solve();
if(testcases) cout << '\n';
#ifdef LOCAL
else
cout << '\n';
cout << "________________________" << endl;
#endif
}
#ifdef LOCAL
cout << "done" << endl;
#endif
return 0;
}
