#include <bits/stdc++.h>
using namespace std;
template<class T>
struct Fenwick {
int n;
vector<T> bit;
Fenwick(int n) : n(n), bit(n + 1, 0) {}
void add(int i, T delta) {
for (i++; i <= n; i += i & -i) {
bit[i] += delta;
}
}
void add(int l, int r, T delta) {
add(l, +delta);
add(r, -delta);
}
T get(int i) {
T res = 0;
for (i++; i > 0; i -= i & -i) {
res += bit[i];
}
return res;
}
};
struct Tree {
const int LOG = 17;
int n;
vector<vector<int>> adj;
vector<int> begin, end;
int tim;
vector<int> depth;
vector<vector<int>> lift;
Tree(int n, vector<vector<int>> adj) : n(n), adj(adj), depth(n), lift(n, vector<int>(LOG, -1)), begin(n), end(n), tim(0) {
function<void(int, int)> dfs = [&](int u, int p) {
begin[u] = tim++;
depth[u] = p == -1 ? 0 : depth[p] + 1;
lift[u][0] = p;
for (int i = 1; i < LOG; i++) {
int v = lift[u][i - 1];
if (v != -1) {
lift[u][i] = lift[v][i - 1];
}
}
for (int v : adj[u]) {
if (v == p) continue;
dfs(v, u);
}
end[u] = tim;
};
dfs(0, -1);
}
int pos(int u) {
return begin[u];
}
int pos(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
return begin[v];
}
array<int, 2> subtree(int u) {
return array<int, 2>{ begin[u], end[u] };
}
array<int, 2> subtree(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
return array<int, 2>{ begin[v], end[v] };
}
int lca(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
for (int i = LOG - 1; i >= 0; i--) {
int w = lift[v][i];
if (w != -1 && depth[w] >= depth[u]) {
v = w;
}
}
if (u == v) return u;
for (int i = LOG - 1; i >= 0; i--) {
if (lift[u][i] != lift[v][i]) {
u = lift[u][i];
v = lift[v][i];
}
}
return lift[u][0];
}
};
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
// freopen("inp.inp", "r", stdin);
// freopen("out.out", "w", stdout);
int n, m, q;
cin >> n >> m >> q;
vector<vector<int>> adj(n);
vector<array<int, 2>> edges(n - 1);
for (int i = 0; i < n - 1; i++) {
int u, v;
cin >> u >> v;
u--;
v--;
adj[u].push_back(v);
adj[v].push_back(u);
edges[i] = { u, v };
}
Tree tree(n, adj);
vector<array<int, 2>> checkpoints(m);
for (int i = 0; i < m; i++) {
int p, c;
cin >> p >> c;
p--;
checkpoints[i] = { p, c };
}
sort(checkpoints.begin(), checkpoints.end(), [&](array<int, 2> e0, array<int, 2> e1) { return e0[1] < e1[1]; });
struct Query {
int l, r; // number of silver piles to consider and still good, try to maximize this
int u, v, uv;
int x;
long long y;
};
vector<Query> qs(q);
vector<vector<int>> inbox(m + 1);
for (int i = 0; i < q; i++) {
int u, v, x;
long long y;
cin >> u >> v >> x >> y;
u--;
v--;
qs[i] = { 0, m, u, v, tree.lca(u, v), x, y };
inbox[(qs[i].l + qs[i].r + 1) >> 1].push_back(i);
}
const int LOG = 20;
for (int ite = 0; ite < LOG; ite++) {
Fenwick<long long> fen(n);
vector<vector<int>> new_inbox(m + 1);
for (int t = 0; t <= m; t++) {
for (int i : inbox[t]) {
auto &[l, r, u, v, uv, x, y] = qs[i];
long long sum = fen.get(tree.pos(u)) + fen.get(tree.pos(v)) - 2 * fen.get(tree.pos(uv));
if (sum <= y) {
l = t;
} else {
r = t - 1;
}
new_inbox[(l + r + 1) >> 1].push_back(i);
}
if (t != m) {
auto [p, c] = checkpoints[t];
auto [ql, qr] = tree.subtree(edges[p][0], edges[p][1]);
fen.add(ql, qr, +c);
}
}
inbox = new_inbox;
}
Fenwick<int> fen0(n);
for (int t = 0; t < m; t++) {
auto [p, c] = checkpoints[t];
auto [ql, qr] = tree.subtree(edges[p][0], edges[p][1]);
fen0.add(ql, qr, +1);
}
Fenwick<int> fen(n);
vector<int> ans(q);
for (int t = 0; t <= m; t++) {
for (int i : inbox[t]) {
auto [l, r, u, v, uv, x, y] = qs[i];
int cnt0 = fen0.get(tree.pos(u)) + fen0.get(tree.pos(v)) - 2 * fen0.get(tree.pos(uv));
int cnt = fen.get(tree.pos(u)) + fen.get(tree.pos(v)) - 2 * fen.get(tree.pos(uv));
int req = cnt0 - cnt;
ans[i] = max(-1, x - req);
}
if (t != m) {
auto [p, c] = checkpoints[t];
auto [ql, qr] = tree.subtree(edges[p][0], edges[p][1]);
fen.add(ql, qr, +1);
}
}
for (int x : ans) {
cout << x << '\n';
}
}
