#include<bits/stdc++.h>
using namespace std;
#define int long long
#define vec vector
const int N = 1<<17;
const int CMX = (int)1<<31;
struct Node {
int cnt = 0;
int sum = 0;
Node* left = nullptr;
Node* right = nullptr;
Node* get_right() {
if(right == nullptr) {
right = new Node{};
}
return right;
}
Node* get_left() {
if(left == nullptr) {
left = new Node{};
}
return left;
}
void insert(int val, int l = 0, int r = CMX) {
cnt++;
sum += val;
if(l+1 == r) return;
int m = (l+r)/2;
if(val >= m) {
get_right()->insert(val, m, r);
}
else {
get_left()->insert(val, l, m);
}
}
~Node() {
delete left;
delete right;
}
};
Node roots[N*3];
void insert(int i, int val) {
i += N;
roots[i].insert(val);
while(i > 1) {
i /= 2;
roots[i].insert(val);
}
}
int tree_sz[N];
int ri[N];
int t = 0;
int depth[N];
vec<int> tree[N];
int par[N];
void dfs1(int u = 0, int p = -1) {
par[u] = p;
tree_sz[u] = 1;
for(int v : tree[u]) {
if(v == p) continue;
depth[v] = depth[u]+1;
dfs1(v, u);
tree_sz[u] += tree_sz[v];
}
}
int head[N];
void heavy_light(int u = 0, int p = -1) {
ri[u] = t++;
pair<int, int> mxch{-1, -1};
for(int v : tree[u]) {
if(v == p) continue;
if(tree_sz[v] > mxch.second) {
mxch = {v, tree_sz[v]};
}
}
if(mxch.first == -1) return;
head[mxch.first] = head[u];
heavy_light(mxch.first, u);
for(int v : tree[u]) {
if(v == p || v == mxch.first) {
continue;
}
head[v] = v;
heavy_light(v, u);
}
}
void tree_range_indices(int l, int r, vec<int>& res, int i = 1, int tl = 0, int tr = N) {
if(tl >= r || tr <= l) return;
if(tl >= l && tr <= r) {
res.push_back(i);
return;
}
int tm = (tl + tr)/2;
tree_range_indices(l, r, res, i*2, tl, tm);
tree_range_indices(l, r, res, i*2+1, tm, tr);
}
vec<int> range_indices(int u, int v) {
vec<int> res = {};
while(true) {
if(head[u] == head[v]) {
if(depth[u] > depth[v]) swap(u, v);
tree_range_indices(ri[u]+1, ri[v]+1, res);
break;
}
if(depth[head[u]] < depth[head[v]]) swap(u, v);
if(head[u] == u) {
tree_range_indices(ri[u], ri[u]+1, res);
u = par[u];
}
else {
tree_range_indices(ri[head[u]]+1, ri[u]+1, res);
u = head[u];
}
//cerr << "STUCK 2" << '\n';
}
return res;
}
int32_t main() {
int n, m, q;
cin >> n >> m >> q;
map<int, pair<int, int>> edges;
for(int i = 0; i<n-1; i++) {
int u, v;
cin >> u >> v;
u--;v--;
tree[u].push_back(v);
tree[v].push_back(u);
edges.insert({i, {u, v}});
}
dfs1();
heavy_light();
for(int i = 0; i<m; i++) {
int ei, c;
cin >> ei >> c;
ei--;
auto [u, v] = edges[ei];
if(depth[u] > depth[v]) swap(u, v);
insert(ri[v], c);
}
for(int i = 0; i<q; i++) {
int u, v, s, g;
cin >> u >> v >> g >> s;
u--; v--;
vec<int> root_inds = range_indices(u, v);
vec<Node*> nodes(root_inds.size());
int tot_cnt = 0;
for(int i = 0; i<root_inds.size(); i++) {
nodes[i] = &roots[root_inds[i]];
tot_cnt += nodes[i]->cnt;
}
int sum = 0;
int cnt = 0;
int l = 0;
int r = CMX;
while(l+1 != r) {
int m = (l+r)/2;
int cand_sum = sum;
int cand_cnt = cnt;
for(int i = 0; i<nodes.size(); i++) {
cand_sum += nodes[i]->get_left()->sum;
cand_cnt += nodes[i]->get_left()->cnt;
}
if(cand_sum <= s) {
l = m;
sum = cand_sum;
cnt = cand_cnt;
for(int i = 0; i<nodes.size(); i++) {
nodes[i] = nodes[i]->get_right();
}
}
else {
r = m;
for(int i = 0; i<nodes.size(); i++) {
nodes[i] = nodes[i]->get_left();
}
}
//cerr << "STUCK 1" << '\n';
}
cerr << tot_cnt << ' ' << cnt << ' ' << g << '\n';
assert(sum <= s);
if(g < tot_cnt-cnt) cout << -1 << endl;
else cout << g-(tot_cnt-cnt) << endl;
}
}
