#include<iostream>
#include<vector>
#include<algorithm>
#include<utility>
using namespace std;
typedef long long ll;
int n, m, q, sz;
vector<vector<int>> pts, graph;
vector<pair<int, int>> edges;
vector<ll> cp;
struct Query{
int s, t;
ll x, y;
int id;
Query(int _s, int _t, ll _x, ll _y, int _id){
s = _s, t = _t, x = _x, y = _y, id = _id;
}
};
vector<Query> queries;
vector<ll> ans;
vector<vector<int>> anc;
vector<int> in, out, dep;
int cnt = 0;
void dfs(int node, int parent){
in[node] = ++cnt;
anc[0][node] = parent;
dep[node] = dep[parent] + 1;
for(auto &x: graph[node]){
if(x == parent) continue;
dfs(x, node);
}
out[node] = cnt;
}
vector<ll> bit, bit2;
void modify(int pos, ll num){
while(pos <= n){
bit[pos] += num;
pos += (pos & -pos);
}
}
ll query(int pos){
ll ans = 0;
while(pos > 0){
ans += bit[pos];
pos -= (pos & -pos);
}
return ans;
}
void modify2(int pos, ll num){
while(pos <= n){
bit2[pos] += num;
pos += (pos & -pos);
}
}
ll query2(int pos){
ll ans = 0;
while(pos > 0){
ans += bit2[pos];
pos -= (pos & -pos);
}
return ans;
}
int lca(int a, int b){
if(dep[a] < dep[b]) swap(a, b);
for(int i = 0; i < 18; i++){
if((dep[a] - dep[b]) & (1 << i)) a = anc[i][a];
}
for(int i = 17; i >= 0; i--){
if(anc[i][a] != anc[i][b]){
a = anc[i][a];
b = anc[i][b];
}
}
if(a != b){
a = anc[0][a];
b = anc[0][b];
}
return a;
}
void add(int l, int r){
for(int i = l; i <= r; i++){
ll val = cp[i - 1];
for(auto &x: pts[i]){
auto [a, b] = edges[x];
if(dep[a] < dep[b]) swap(a, b);
modify(in[a], val);
if(out[a] < n) modify(out[a] + 1, -val);
modify2(in[a], -1);
if(out[a] < n) modify2(out[a] + 1, 1);
}
}
}
void rollback(int l, int r){
for(int i = l; i <= r; i++){
ll val = cp[i - 1];
for(auto &x: pts[i]){
auto [a, b] = edges[x];
if(dep[a] < dep[b]) swap(a, b);
modify(in[a], -val);
if(out[a] < n) modify(out[a] + 1, val);
modify2(in[a], 1);
if(out[a] < n) modify2(out[a] + 1, -1);
}
}
}
void f(int l, int r, vector<Query>& queries){
if(l == r){
add(l, r);
for(auto &[s, t, x, y, id]: queries){
ll ag = query(in[s]) + query(in[t]) - 2 * query(in[lca(s, t)]), au = query2(in[s]) + query2(in[t]) - 2 * query2(in[lca(s, t)]);
if(ag <= y && au <= x) ans[id] = x - au;
else ans[id] = -1;
//cout << id << " " << ag << " " << au << "\n";
}
rollback(l, r);
if(l == 1){
for(auto &[s, t, x, y, id]: queries){
ll ag = query(in[s]) + query(in[t]) - 2 * query(in[lca(s, t)]), au = query2(in[s]) + query2(in[t]) - 2 * query2(in[lca(s, t)]);
if(ans[id] == -1){
if(au <= x) ans[id] = x - au;
}
}
}
return;
}
int mid = ((l + r) >> 1) + 1;
add(l, mid);
vector<Query> ql, qr;
for(auto &[s, t, x, y, id]: queries){
ll ag = query(in[s]) + query(in[t]) - 2 * query(in[lca(s, t)]), au = query2(in[s]) + query2(in[t]) - 2 * query2(in[lca(s, t)]);
if(ag > y) ql.emplace_back(s, t, x, y, id);
else qr.emplace_back(s, t, x, y, id);
//cout << id << " " << mid << " " << ag << " " << au << "\n";
}
vector<Query>().swap(queries);
rollback(mid, mid);
f(mid, r, qr);
rollback(l, mid - 1);
f(l, mid - 1, ql);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> q;
graph.resize(n + 1);
pts.resize(m + 1);
edges.resize(n);
ans.resize(q);
anc.resize(18, vector<int>(n + 1));
in.resize(n + 1);
out.resize(n + 1);
dep.resize(n + 1);
bit2.resize(n + 1);
bit.resize(n + 1);
ll a, b;
for(int i = 1; i < n; i++){
cin >> a >> b;
graph[a].push_back(b);
graph[b].push_back(a);
edges[i] = make_pair(a, b);
}
vector<pair<int, ll>> chktmp;
for(int i = 1; i <= m; i++){
cin >> a >> b;
chktmp.emplace_back(a, b);
cp.push_back(b);
}
sort(cp.begin(), cp.end());
vector<int> cntt(m + 1);
for(auto &[id, val]: chktmp){
val = lower_bound(cp.begin(), cp.end(), val) - cp.begin() + 1;
cntt[val]++;
val += cntt[val] - 1;
pts[val].push_back(id);
}
sz = cp.size();
for(int i = 0; i < q; i++){
int s, t;
ll x, y;
cin >> s >> t >> x >> y;
queries.emplace_back(s, t, x, y, i);
}
dfs(1, 1);
for(int i = 1; i < 18; i++){
for(int j = 1; j <= n; j++){
anc[i][j] = anc[i - 1][anc[i - 1][j]];
}
}
for(int i = 1; i <= sz; i++){
for(auto &x: pts[i]){
auto [a, b] = edges[x];
if(dep[a] < dep[b]) swap(a, b);
modify2(in[a], 1);
if(out[a] < n) modify2(out[a] + 1, -1);
}
}
f(1, sz, queries);
for(int i = 0; i < q; i++) cout << ans[i] << "\n";
}
// g++ -std=gnu++20 pA.cpp -o run -Wall -Wextra -fsanitize=undefined -fsanitize=address
