// author: erray
#include <bits/stdc++.h>
#ifdef DEBUG
#include "debug.h"
#else
#define debug(...) void(37)
#endif
using namespace std;
template<typename T, typename F = function<T(const T&, const T&)>>
struct SparseTable {
vector<vector<T>> a;
int n;
F op;
SparseTable() { }
SparseTable(vector<T> _a, F _op) : op(_op) {
n = int(_a.size());
int lg = 32 - __builtin_clz(n);
a.resize(lg);
a[0] = _a;
for (int j = 1; j < lg; ++j) {
int size = n - (1 << j) + 1;
a[j].resize(size);
for (int i = 0; i < size; ++i) {
a[j][i] = op(a[j - 1][i], a[j - 1][i + ((1 << (j - 1)))]);
}
}
}
T get(int l, int r) {
assert(l >= 0 && r < n && l <= r);
int lg = __lg(r - l + 1);
return op(a[lg][l], a[lg][r + 1 - (1 << lg)]);
}
};
template<typename T>
struct Fenwick {
vector<T> tree;
int n;
Fenwick(int _n) : n(_n) {
tree.resize(n + 1);
}
T get(int x) {
x += 1;
T res = 0;
while (x > 0) {
res += tree[x];
x -= x & -x;
}
return res;
}
void modify(int x, T d) {
x += 1;
while (x <= n) {
tree[x] += d;
x += x & -x;
}
}
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int N, M, Q;
cin >> N >> M >> Q;
vector<int> A(N - 1), B(N - 1);
vector<vector<int>> g(N);
for (int i = 0; i < N - 1; ++i) {
cin >> A[i] >> B[i];
--A[i], --B[i];
g[A[i]].push_back(i);
g[B[i]].push_back(i);
}
vector<array<int, 2>> C(M);
for (int i = 0; i < M; ++i) {
cin >> C[i][1] >> C[i][0];
--C[i][1];
}
sort(C.begin(), C.end());
vector<int> S(Q), T(Q), X(Q);
vector<long long> Y(Q);
for (int i = 0; i < Q; ++i) {
cin >> S[i] >> T[i] >> X[i] >> Y[i];
--S[i], --T[i];
}
vector<int> tin(N), tout(N), d(N), tour;
function<void(int, int)> Dfs = [&](int v, int pr) {
tin[v] = int(tour.size());
tour.push_back(v);
bool leaf = true;
for (auto id : g[v]) {
int u = A[id] ^ B[id] ^ v;
if (u == pr) {
continue;
}
if (A[id] == u) {
swap(A[id], B[id]);
}
d[u] = d[v] + 1;
Dfs(u, v);
tout[v] = int(tour.size());
tour.push_back(v);
leaf = false;
}
if (leaf) {
tout[v] = int(tour.size());
tour.push_back(v);
}
};
Dfs(0, -1);
debug(d, tour, tin, tout);
int s = int(tour.size());
for (int i = 0; i < Q; ++i) {
if (tin[S[i]] > tin[T[i]]) {
swap(S[i], T[i]);
}
}
for (int i = 0; i < M; ++i) {
C[i][1] = B[C[i][1]];
}
SparseTable st(tour, [&](int x, int y) {
return d[x] < d[y];
});
auto Lca = [&](int x, int y) {
return (tout[x] >= tout[y] ? x : st.get(tout[x], tin[y]));
};
auto Get = [&]<typename T>(int x, int y, Fenwick<T>& ft) -> T {
return ft.get(tin[x]) + ft.get(tin[y]) - 2 * ft.get(Lca(x, y));
};
auto Modify = [&]<typename T>(int x, int delta, Fenwick<T>& ft) {
ft.modify(tin[x], delta);
ft.modify(tout[x], -delta);
};
debug(C);
Fenwick<long long> sum(s);
int p = 0;
vector<vector<int>> point(M + 1);
function<void(vector<int>, int l, int r)> Pbs = [&](vector<int> qs, int l, int r) {
if (l == r) {
point[l] = qs;
return;
}
debug(l, r, qs);
int mid = 1 + ((l + r) >> 1);
while (p < mid) {
Modify(C[p][1], C[p][0], sum);
++p;
}
while (mid < p) {
--p;
Modify(C[p][1], -C[p][0], sum);
}
vector<int> left, right;
for (auto i : qs) {
(Get(S[i], T[i], sum) > Y[i] ? left : right).push_back(i);
}
Pbs(left, l, mid - 1);
Pbs(right, mid, r);
};
vector<int> foo(Q);
iota(foo.begin(), foo.end(), 0);
Pbs(foo, 0, M);
debug(point);
Fenwick<int> cnt(s);
for (int i = 0; i <= M; ++i) {
for (auto id : point[i]) {
X[id] += Get(S[id], T[id], cnt);
}
if (i < M) {
Modify(C[i][1], +1, cnt);
}
}
debug(X);
for (int i = 0; i < Q; ++i) {
X[i] -= Get(S[i], T[i], cnt);
}
for (int i = 0; i < Q; ++i) {
cout << max(X[i], -1) << '\n';
}
}
