#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int N, M, Q, timer;
vector<int> sz, pos, dep, par, top;
vector<vector<int>> adj;
struct S {
S *l, *r; ll s;
S() {l = r = nullptr; s = 0;}
S(ll a) {l = r = nullptr; s = a;}
S(S *x) : l(x->l), r(x->r), s(x->s) {}
S(S *u, S *v) : l(u), r(v), s(0) {
if (l) s += l->s;
if (r) s += r->s;
}
};
vector<S*> roots;
S* build(int l, int r) {
if (l + 1 == r) return new S(0LL);
int m = (l + r) / 2;
return new S(build(l, m), build(m, r));
}
S* upd(S* i, int l, int r, int j, ll v) {
if (l + 1 == r) return new S(i->s + v);
int m = (l + r) / 2; return j < m
? new S(upd(i->l, l, m, j, v), i->r)
: new S(i->l, upd(i->r, m, r, j, v));
}
ll qry(S* i, int l, int r, int L, int R) {
if (R <= l || r <= L) return 0;
if (L <= l && r <= R) return i->s;
int m = (l + r) / 2;
return qry(i->l, l, m, L, R) + qry(i->r, m, r, L, R);
}
void init(int x) {
sz[x] = 1;
for (auto &y : adj[x]) {
adj[y].erase(find(adj[y].begin(), adj[y].end(), par[y] = x));
dep[y] = dep[x] + 1;
init(y);
sz[x] += sz[y];
if (sz[y] > sz[adj[x][0]]) swap(y, adj[x][0]);
}
}
void dfs(int x) {
pos[x] = timer++;
for (auto y : adj[x]) {
top[y] = y == adj[x][0] ? top[x] : y;
dfs(y);
}
}
ll path(int x, int y, int z) {
ll s = 0;
for (; top[x] != top[y]; x = par[top[x]]) {
if (dep[top[x]] < dep[top[y]]) swap(x, y);
s += qry(roots[z], 0, N, pos[top[x]], pos[x] + 1);
}
if (dep[x] > dep[y]) swap(x, y);
return s += qry(roots[z], 0, N, pos[x] + 1, pos[y] + 1);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N >> M >> Q;
sz.resize(N);
pos.resize(N);
dep.resize(N);
adj.resize(N);
top.resize(N);
par.resize(N, -1);
vector<pair<int, int>> edges(N - 1);
for (int i = 0; i < N - 1; i++) {
int a, b;
cin >> a >> b;
a--, b--;
edges[i] = {a, b};
adj[a].push_back(i);
adj[b].push_back(i);
}
vector<int> w(N - 1); {
function<void(int, int)> dfs = [&](int x, int p) {
for (auto &y : adj[x]) {
int i = y;
auto [u, v] = edges[y];
y = x ^ u ^ v;
if (y == p) continue;
w[i] = y;
dfs(y, x);
}
};
dfs(0, -1);
}
init(0); dfs(0);
roots.push_back(build(0, N));
vector<pair<int, int>> ch(M);
for (int i = 0; i < M; i++) {
int e, s;
cin >> e >> s; e--;
ch[i] = {s, w[e]};
}
sort(ch.begin(), ch.end());
for (auto [s, i] : ch) {
roots.push_back(upd(roots.back(), 0, N, pos[i], s));
}
vector<vector<int>> a(M + 1);
vector<int> S(Q), T(Q), X(Q), ans(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]--;
int lo = 0, hi = M;
while (lo < hi) {
int mi = (lo + hi + 1) / 2;
path(S[i], T[i], mi) <= Y[i] ? lo = mi : hi = mi - 1;
}
a[lo].push_back(i);
}
roots.resize(1);
for (int i = M; i >= 0; i--) {
if (i < M) {
auto [s, j] = ch[i];
roots.push_back(upd(roots.back(), 0, N, pos[j], 1));
}
for (auto j : a[i]) {
ans[j] = max<ll>(-1, X[j] - path(S[j], T[j], M - i));
}
}
for (int i = 0; i < Q; i++) cout << ans[i] << "\n";
return 6/22;
}
