#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int N, M, Q;
cin >> N >> M >> Q;
vector<pair<int, int>> edges(N - 1);
vector<vector<pair<int, int>>> adj(N);
for (int i = 0; i < N - 1; i++) {
int x, y;
cin >> x >> y;
x--, y--;
edges[i] = {x, y};
adj[x].emplace_back(y, i);
adj[y].emplace_back(x, i);
}
vector<int> P(M), C(M);
vector<vector<int>> c(N - 1);
for (int i = 0; i < M; i++) {
cin >> P[i] >> C[i];
P[i]--;
c[P[i]].push_back(C[i]);
}
if (C == vector(M, C[0])) {
vector<int> cnt(N - 1);
for (int i = 0; i < M; i++) {
cnt[P[i]]++;
}
vector<int> f(N), dep(N);
vector par(N, vector<int>(20, -1));
auto dfs = [&](auto dfs, int x) -> void {
for (int i = 0; i < 19 && par[x][i] != -1; i++) {
par[x][i + 1] = par[par[x][i]][i];
}
for (auto [y, z] : adj[x]) {
if (y != par[x][0]) {
dep[y] = dep[x] + 1;
f[y] = f[x] + cnt[z];
par[y][0] = x;
dfs(dfs, y);
}
}
};
dfs(dfs, 0);
auto lca = [&](int x, int y) {
if (dep[x] < dep[y]) {
swap(x, y);
}
for (int i = 0; i < 20; i++) {
if ((dep[x] - dep[y]) >> i & 1) {
x = par[x][i];
}
}
if (x == y) {
return x;
}
for (int i = 19; i >= 0; i--) {
if (par[x][i] != par[y][i]) {
x = par[x][i];
y = par[y][i];
}
}
return par[x][0];
};
while (Q--) {
int S, T, X; ll Y;
cin >> S >> T >> X >> Y;
S--, T--;
int k = f[S] + f[T] - 2 * f[lca(S, T)];
cout << max(-1LL, X - max(0LL, k - Y / C[0])) << "\n";
}
return 0;
}
if (N <= 2000 && M <= 2000 && Q <= 2000) {
while (Q--) {
int S, T, X; ll Y;
cin >> S >> T >> X >> Y;
S--, T--;
vector<int> p(N, -1);
queue<int> q;
p[S] = S;
q.push(S);
while (!q.empty()) {
int x = q.front();
q.pop();
for (auto [y, z] : adj[x]) {
if (p[y] == -1) {
p[y] = z;
q.push(y);
}
}
}
priority_queue<int, vector<int>, greater<int>> pq;
while (T != S) {
for (int v : c[p[T]]) {
pq.push(v);
}
auto [x, y] = edges[p[T]];
T ^= x ^ y;
}
while (!pq.empty() && pq.top() <= Y) {
Y -= pq.top();
pq.pop();
}
X -= pq.size();
X = max(X, -1);
cout << X << "\n";
}
return 0;
}
vector<int> S(Q), T(Q), X(Q);
vector<ll> Y(Q);
for (int i = 0; i < Q; i++) {
cin >> S[i] >> T[i] >> X[i] >> Y[i];
S[i]--, T[i]--;
if (S[i] > T[i]) {
swap(S[i], T[i]);
}
}
vector<pair<int, int>> ch(M);
for (int i = 0; i < M; i++) {
ch[i] = {C[i], P[i]};
}
sort(ch.begin(), ch.end());
vector<int> lo(Q), hi(Q, M);
vector<ll> bit(N);
auto add = [&](int i, int v) {
for (i++; i < N; i += i & -i) {
bit[i] += v;
}
};
auto sum = [&](int i) {
ll s = 0;
for (; i; i -= i & -i) {
s += bit[i];
}
return s;
};
for (int z = 0; z < 20; z++) {
vector<int> mi(Q);
vector<vector<int>> f(M);
for (int i = 0; i < Q; i++) {
if (lo[i] != hi[i]) {
mi[i] = (lo[i] + hi[i] + 1) / 2;
f[mi[i] - 1].push_back(i);
}
}
bit.assign(N, 0);
for (int i = 0; i < M; i++) {
auto [c, p] = ch[i];
add(p, c);
for (int j : f[i]) {
if (sum(T[j]) - sum(S[j]) <= Y[j]) {
lo[j] = i + 1;
} else {
hi[j] = i;
}
}
}
}
vector<ll> ans(Q);
vector<vector<int>> f(M + 1);
for (int i = 0; i < Q; i++) {
f[lo[i]].push_back(i);
}
bit.assign(N, 0);
for (int i = M; i >= 0; i--) {
if (i < M) {
auto [c, p] = ch[i];
add(p, 1);
}
for (int j : f[i]) {
ans[j] = max(-1LL, X[j] - sum(T[j]) + sum(S[j]));
}
}
for (int i = 0; i < Q; i++) {
cout << ans[i] << " \n"[i == Q - 1];
}
return 6/22;
}
