#include <bits/stdc++.h>
using namespace std;
void main_program();
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0);
main_program();
}
#define int long long
using ii = pair<int, int>;
struct Segtree{
vector<int> tree;
int _n;
Segtree() = default;
Segtree(int N): tree(4*N), _n(N) {}
int get(int pos) { return get(1, 0, _n - 1, pos); }
int get(int i, int l, int r, int pos){
if (l == pos && r == pos) return tree[i];
int mid = (l + r) >> 1;
if (pos <= mid) return tree[i] + get(i<<1, l, mid, pos);
else return tree[i] + get(i<<1|1, mid+1, r, pos);
}
void update(int tl, int tr, int delta) { update(1, 0, _n - 1, tl, tr, delta); }
void update(int i, int l, int r, int tl, int tr, int delta){
if (tl <= l && r <= tr) tree[i] += delta;
else if (tl > r || tr < l) return;
else{
int mid = (l + r) >> 1;
update(i<<1, l, mid, tl, tr, delta);
update(i<<1|1, mid+1, r, tl, tr, delta);
}
}
};
template <class T>
struct RMQ{
vector<vector<T>> table;
int _n, _lg;
RMQ() = default;
RMQ(vector<T> &V){
_n = V.size();
_lg = 64 - __builtin_clzll(_n);
table.assign(_lg, vector<T>(_n));
table[0] = V;
for (int j = 1; j < _lg; j++){
for (int i = 0; i + (1 << j) <= _n; i++){
table[j][i] = min(table[j-1][i], table[j-1][i + (1 << (j-1))]);
}
}
}
T get(int l, int r){
if (l > r) swap(l, r);
int j = 63 - __builtin_clzll(r - l + 1);
return min(table[j][l], table[j][r - (1 << j) + 1]);
}
};
struct Query{
int a, b;
int lca;
int gold, silver;
int idx;
};
struct PBS{
int lb, rb;
vector<Query> qs;
};
int n, m, q;
vector<vector<int>> adj;
vector<ii> edges;
vector<ii> checkpoints;
vector<Query> all_queries;
int timer = 0;
vector<int> tin, tout, occ;
vector<ii> eulertour;
RMQ<ii> rmq;
vector<int> max_silver;
void dfs_euler(int x, int p = -1, int d = 0){
tin[x] = timer++;
occ[x] = eulertour.size();
eulertour.emplace_back(d, x);
for (auto k: adj[x]){
if (k == p) continue;
dfs_euler(k, x, d+1);
eulertour.emplace_back(d, x);
}
tout[x] = timer - 1;
}
inline int LCA(int x, int y){
return rmq.get(occ[x], occ[y]).second;
}
void main_program(){
cin >> n >> m >> q;
adj.resize(n);
edges.resize(n-1);
checkpoints.resize(m);
all_queries.resize(q);
tin.resize(n);
tout.resize(n);
occ.resize(n);
max_silver.resize(q);
for (int i = 0; i < n-1; i++){
int x, y; cin >> x >> y;
x--; y--;
adj[x].push_back(y);
adj[y].push_back(x);
edges[i] = {x, y};
}
for (int i = 0; i < m; i++){
int P, cost; cin >> P >> cost;
P--;
checkpoints[i] = {P, cost};
}
sort(checkpoints.begin(), checkpoints.end(), [](ii A, ii B){
return A.second < B.second;
});
dfs_euler(0);
rmq = RMQ<ii>(eulertour);
for (int i = 0; i < n-1; i++){
if (tin[edges[i].first] > tin[edges[i].second])
swap(edges[i].first, edges[i].second);
}
for (int i = 0; i < q; i++){
int a, b, gold, silver;
cin >> a >> b >> gold >> silver;
a--; b--;
int lca = LCA(a, b);
all_queries[i] = Query{a, b, lca, gold, silver, i};
}
vector<PBS> crrpbs = {PBS{0, m, all_queries}};
while (!crrpbs.empty()){
vector<PBS> nxtpbs;
int prev = -1;
Segtree st(n);
Segtree stcnt(n);
for (auto range: crrpbs){
if (range.lb == range.rb){
for (int i = prev + 1; i < range.lb; i++){
auto [P, cost] = checkpoints[i];
int x = edges[P].second;
st.update(tin[x], tout[x], cost);
stcnt.update(tin[x], tout[x], 1);
}
prev = max(prev, range.lb - 1);
for (auto query: range.qs){
max_silver[query.idx] =
stcnt.get(tin[query.a]) + stcnt.get(tin[query.b]) - stcnt.get(tin[query.lca]) * 2;
}
continue;
}
int mid = (range.lb + range.rb) >> 1;
for (int i = prev + 1; i <= mid; i++){
auto [P, cost] = checkpoints[i];
int x = edges[P].second;
st.update(tin[x], tout[x], cost);
stcnt.update(tin[x], tout[x], 1);
}
prev = max(prev, mid);
PBS leftnode{range.lb, mid, {}}, rightnode{mid+1, range.rb, {}};
for (auto query: range.qs){
int silver_cost = st.get(tin[query.a]) + st.get(tin[query.b]) - st.get(tin[query.lca]) * 2;
if (silver_cost <= query.silver) rightnode.qs.push_back(query);
else leftnode.qs.push_back(query);
}
if (!leftnode.qs.empty()) nxtpbs.push_back(leftnode);
if (!rightnode.qs.empty()) nxtpbs.push_back(rightnode);
}
crrpbs.swap(nxtpbs);
}
Segtree st(n);
for (auto pt: checkpoints){
int x = edges[pt.first].second;
st.update(tin[x], tout[x], 1);
}
for (int i = 0; i < q; i++){
auto query = all_queries[i];
int cnt_pt = st.get(tin[query.a]) + st.get(tin[query.b]) - st.get(tin[query.lca]) * 2;
int gold_cost = cnt_pt - max_silver[i];
if (gold_cost > query.gold) cout << "-1\n";
else cout << query.gold - gold_cost << "\n";
}
}
