/*
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,fma,bmi,bmi2,sse4.2,popcnt,lzcnt")
*/
#include <bits/stdc++.h>
#define taskname ""
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define ll long long
#define ld long double
#define pb push_back
#define ff first
#define ss second
#define pii pair<int, int>
#define vi vector<int>
#define vii vector<pii>
#define isz(x) (int)x.size()
using namespace std;
const int mxN = 2e5 + 5;
const int mod = 1e9 + 7;
const ll oo = 1e18;
struct query {
int s, t, x, y;
query(int s, int t, int x, int y) : s(s), t(t), x(x), y(y) {}
};
vi pos, G[mxN];
vii edges, points;
vector<query> queries;
pii euler_tour[20][2 * mxN];
int n, m, q, a[mxN], ans[mxN], cp[mxN];
int tin[mxN], tout[mxN], dep[mxN], ap[mxN], timer, ecnt;
void dfs(int v, int p) {
tin[v] = ++timer, dep[v] = dep[p] + 1;
euler_tour[0][++ecnt] = pair{dep[v], v}, ap[v] = ecnt;
for(int u : G[v]) {
if(u == p) continue;
dfs(u, v);
euler_tour[0][++ecnt] = pair{dep[v], v};
}
tout[v] = timer;
}
void build_sparse() {
for(int p = 1, i = 1; p << 1 <= ecnt; p <<= 1, ++i)
for(int j = 1; j <= ecnt - (p << 1) + 1; ++j)
euler_tour[i][j] = min(euler_tour[i - 1][j], euler_tour[i - 1][j + p]);
}
int LCA(int u, int v) {
int l = ap[u], r = ap[v];
if(l > r) swap(l, r);
int len = r - l + 1, lg_len = __lg(len);
return min(euler_tour[lg_len][l], euler_tour[lg_len][r - (1 << lg_len) + 1]).ss;
}
pii fenw[mxN];
void update(int idx, int val1, int val2) {
for(; idx <= n; idx += (idx & (-idx)))
fenw[idx].ff += val1, fenw[idx].ss += val2;
}
void update_range(int l, int r, int val1, int val2) {
update(l, val1, val2);
update(r + 1, -val1, -val2);
}
pii get(int idx) {
pii res = pair{0, 0};
for(; idx; idx -= (idx & (-idx)))
res.ff += fenw[idx].ff, res.ss += fenw[idx].ss;
return res;
}
pii add(pii x, pii y) {
return pair{x.ff + y.ff, x.ss + y.ss};
}
pii sub(pii x, pii y) {
return pair{x.ff - y.ff, x.ss - y.ss};
}
pii mul(pii x, int val) {
return pair{x.ff * val, x.ss * val};
}
void pbs(int l, int r, vi &all_query) {
if(l > r) return;
vi left, right;
int mid = (l + r) >> 1;
for(int i = l; i <= mid; ++i) {
pii tmp = points[i], edge = edges[tmp.ff];
if(dep[edge.ff] > dep[edge.ss]) swap(edge.ff, edge.ss);
update_range(tin[edge.ss], tout[edge.ss], tmp.ss, 1);
}
for(auto &idx : all_query) {
auto [s, t, x, y] = queries[idx];
int lca = LCA(s, t);
pii res = pair{0, 0};
res = add(res, get(tin[s]));
res = add(res, get(tin[t]));
res = sub(res, mul(get(tin[lca]), 2));
if(res.ff <= y) {
ans[idx] = max(ans[idx], x - (cp[s] + cp[t] - 2 * cp[lca] - res.ss));
right.emplace_back(idx);
}
else left.emplace_back(idx);
}
if(l == r) {
pii tmp = points[mid], edge = edges[tmp.ff];
if(dep[edge.ff] > dep[edge.ss]) swap(edge.ff, edge.ss);
update_range(tin[edge.ss], tout[edge.ss], -tmp.ss, -1);
return;
}
if(!right.empty()) {
pbs(mid + 1, r, right);
}
for(int i = l; i <= mid; ++i) {
pii tmp = points[i], edge = edges[tmp.ff];
if(dep[edge.ff] > dep[edge.ss]) swap(edge.ff, edge.ss);
update_range(tin[edge.ss], tout[edge.ss], -tmp.ss, -1);
}
if(!left.empty()) {
pbs(l, mid - 1, left);
}
}
void solve() {
cin >> n >> m >> q;
for(int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
G[u].emplace_back(v);
G[v].emplace_back(u);
edges.emplace_back(u, v);
}
dfs(1, 0);
build_sparse();
for(int i = 1; i <= m; ++i) {
int p, c; cin >> p >> c;
points.emplace_back(--p, c);
pii edge = edges[p];
if(dep[edge.ff] > dep[edge.ss])
swap(edge.ff, edge.ss);
++cp[edge.ss];
}
auto dfs_cp = [&](auto self, int v, int p) -> void {
for(int u : G[v]) {
if(u == p) continue;
cp[u] += cp[v];
self(self, u, v);
}
};
dfs_cp(dfs_cp, 1, 0);
sort(all(points), [&](pii &x, pii &y) {
return x.ss < y.ss;
});
for(int i = 1; i <= q; ++i) {
int s, t, x, y;
cin >> s >> t >> x >> y;
queries.emplace_back(s, t, x, y);
int lca = LCA(s, t);
ans[i - 1] = max(-1ll, x - (cp[s] + cp[t] - 2 * cp[lca]));
}
vi idx(q); iota(all(idx), 0);
pbs(0, m - 1, idx);
for(int i = 0; i < q; ++i)
cout << ans[i] << "\n";
}
signed main() {
#ifndef CDuongg
if(fopen(taskname".inp", "r"))
assert(freopen(taskname".inp", "r", stdin)), assert(freopen(taskname".out", "w", stdout));
#else
freopen("bai3.inp", "r", stdin);
freopen("bai3.out", "w", stdout);
auto start = chrono::high_resolution_clock::now();
#endif
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1; //cin >> t;
while(t--) solve();
#ifdef CDuongg
auto end = chrono::high_resolution_clock::now();
cout << "\n"; for(int i = 1; i <= 100; ++i) cout << '=';
cout << "\nExecution time: " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
#endif
}
