//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,sse,sse2,sse3,ssse3,sse4,abm,popcnt,mmx")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
typedef long double ldb;
typedef complex<double> cd;
constexpr ll INF64 = 9'000'000'000'000'000'000, INF32 = 2'000'000'000, MOD = 1'000'000'007, LOG = 20;
constexpr db PI = acos(-1);
constexpr bool IS_FILE = false, IS_TEST_CASES = false;
random_device rd;
mt19937 rnd32(rd());
mt19937_64 rnd64(rd());
template<typename T>
bool assign_max(T& a, T b) {
if (b > a) {
a = b;
return true;
}
return false;
}
template<typename T>
bool assign_min(T& a, T b) {
if (b < a) {
a = b;
return true;
}
return false;
}
template<typename T>
T square(T a) {
return a * a;
}
template<>
struct std::hash<pair<ll, ll>> {
ll operator() (pair<ll, ll> p) const {
return ((__int128)p.first * MOD + p.second) % INF64;
}
};
struct BIT {
vector<ll> tree;
BIT(ll n) {
tree.resize(n + 1, 0);
}
ll get(ll x) {
ll ans = 0;
for (; x > 0; x -= x & -x) {
ans += tree[x];
}
return ans;
}
void add(ll x, ll y) {
x++;
for (; x < tree.size(); x += x & -x) {
tree[x] += y;
}
}
void clear() {
for (auto& i : tree) {
i = 0;
}
}
};
struct LCA {
vector<vector<ll>> binup;
vector<ll> h;
LCA(vector<vector<ll>>& tree) {
binup.resize(LOG, vector<ll>(tree.size(), 0));
h.resize(tree.size(), -1);
dfs(0, 0, tree);
}
void dfs(ll v, ll p, vector<vector<ll>>& tree) {
h[v] = h[p] + 1;
binup[0][v] = p;
for (ll i = 1; i < LOG; i++) {
binup[i][v] = binup[i - 1][binup[i - 1][v]];
}
for (auto i : tree[v]) {
if (i != p) {
dfs(i, v, tree);
}
}
}
ll get_LA(ll v, ll x) {
for (ll i = 0; i < LOG; i++) {
if ((x >> i) & 1) {
x -= 1 << i;
v = binup[i][v];
}
}
return v;
}
ll get(ll a, ll b) {
if (h[a] < h[b]) {
swap(a, b);
}
a = get_LA(a, h[a] - h[b]);
if (a == b) {
return a;
}
for (ll i = LOG - 1; i >= 0; i--) {
if (binup[i][a] != binup[i][b]) {
a = binup[i][a];
b = binup[i][b];
}
}
return binup[0][a];
}
};
void dfs(ll v, ll p, vector<vector<ll>>& tree, BIT& bi, BIT& bc, vector<vector<pair<ll, ll>>>& cs, vector<vector<pair<ll, ll>>>& qs, vector<pair<ll, ll>>& ans, ll nc) {
for (auto[a, b] : cs[v]) {
bi.add(a, b);
bc.add(a, 1);
nc++;
}
for (auto i : tree[v]) {
if (i != p) {
dfs(i, v, tree, bi, bc, cs, qs, ans, nc);
}
}
for (auto[a, b] : qs[v]) {
ans[b].first = bi.get(a);
ans[b].second = nc - bc.get(a);
}
for (auto[a, b] : cs[v]) {
bi.add(a, -b);
bc.add(a, -1);
}
}
void solve() {
ll n, m, q;
cin >> n >> m >> q;
vector<vector<ll>> tree(n);
vector<pair<ll, ll>> rs;
for (ll i = 1; i < n; i++) {
ll a, b;
cin >> a >> b;
a--;
b--;
rs.emplace_back(a, b);
tree[a].push_back(b);
tree[b].push_back(a);
}
LCA l(tree);
vector<ll> pred;
for (auto[a, b] : rs) {
pred.push_back((l.get(a, b) == a ? b : a));
}
vector<vector<pair<ll, ll>>> cs(n);
vector<pair<ll, ll>> all;
for (ll i = 0; i < m; i++) {
ll p, c;
cin >> p >> c;
p--;
p = pred[p];
all.emplace_back(c, p);
}
sort(all.begin(), all.end());
for (ll i = 0; i < m; i++) {
cs[all[i].second].push_back(make_pair(i, all[i].first));
}
vector<tuple<ll, ll, ll, ll, ll, ll, ll>> qs;
vector<ll> ans;
for (ll i = 0; i < q; i++) {
ll s, t, x, y;
cin >> s >> t >> x >> y;
s--;
t--;
qs.emplace_back(0, m + 1, s, t, l.get(s, t), y, x);
ans.push_back(x + 1);
}
for (ll _ = 0; _ < LOG; _++) {
vector<vector<pair<ll, ll>>> nqs(n);
vector<pair<ll, ll>> anss(q * 3);
BIT bi(m), bc(m);
for (ll i = 0; i < q; i++) {
auto[l, r, s, t, lca, y, x] = qs[i];
ll mid = (l + r) / 2;
nqs[s].emplace_back(mid, i * 3);
nqs[t].emplace_back(mid, i * 3 + 1);
nqs[lca].emplace_back(mid, i * 3 + 2);
}
dfs(0, 0, tree, bi, bc, cs, nqs, anss, 0);
for (ll i = 0; i < q; i++) {
ll na = anss[i * 3].first + anss[i * 3 + 1].first - anss[i * 3 + 2].first * 2;
auto&[l, r, s, t, lca, y, x] = qs[i];
ll mid = (l + r) / 2;
if (na > y) {
r = mid;
} else {
l = mid;
assign_min(ans[i], anss[i * 3].second + anss[i * 3 + 1].second - anss[i * 3 + 2].second * 2);
}
}
}
for (ll i = 0; i < q; i++) {
cout << get<6>(qs[i]) - ans[i] << '\n';
}
}
int main() {
if (IS_FILE) {
freopen("", "r", stdin);
freopen("", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
ll t = 1;
if (IS_TEST_CASES) {
cin >> t;
}
for (ll i = 0; i < t; i++) {
solve();
}
}
