#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long
using i64 = long long;
template <class F, class _S>
bool chmin(F &u, const _S &v){
bool flag = false;
if ( u > v ){
u = v; flag |= true;
}
return flag;
}
template <class F, class _S>
bool chmax(F &u, const _S &v){
bool flag = false;
if ( u < v ){
u = v; flag |= true;
}
return flag;
}
struct Fenw{
vector <int> fenw;
int n;
Fenw(int n) : fenw(n + 1, 0), n(n) {}
void upd(int i, int val){
for (; i <= n; i += i & -i ){
fenw[i] += val;
}
}
int get(int i){
int cnt = 0;
for (; i > 0; i -= i & -i ){
cnt += fenw[i];
}
return cnt;
}
int get(int l, int r){
return get(r) - get(l - 1);
}
};
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, q; cin >> n >> m >> q;
vector <vector<ar<int,2>>> G(n);
for ( int i = 0; i + 1 < n; i++ ){
int u, v; cin >> u >> v;
--u, --v;
G[u].pb({v, i});
G[v].pb({u, i});
}
vector <int> P(m), C(m);
for ( int i = 0; i < m; i++ ){
cin >> P[i] >> C[i];
--P[i];
}
vector <int> S(q), T(q), X(q), Y(q);
for ( int i = 0; i < q; i++ ){
cin >> S[i] >> T[i] >> X[i] >> Y[i];
--S[i], --T[i];
}
vector <vector<int>> up(20, vector <int> (n));
vector <int> d(n), tin(n), tout(n), F(n);
int timer = 0;
auto dfs = [&](auto dfs, int u, int p) -> void{
up[0][u] = p;
for ( int j = 1; j < 20; j++ ){
up[j][u] = up[j - 1][up[j - 1][u]];
}
tin[u] = ++timer;
for ( auto &[v, i]: G[u] ){
if ( v != p ){
F[i] = v;
d[v] = d[u] + 1;
dfs(dfs, v, u);
}
} tout[u] = timer;
};
dfs(dfs, 0, 0);
for ( auto &x: P ){
x = F[x];
}
vector <int> L(q);
for ( int i = 0; i < q; i++ ){
int u = S[i], v = T[i];
if ( d[u] < d[v] ) swap(u, v);
int df = d[u] - d[v];
for ( int i = 0; i < 20; i++ ){
if ( df >> i & 1 ){
u = up[i][u];
}
}
if ( u != v ){
for ( int i = 19; i >= 0; i-- ){
if ( up[i][u] != up[i][v] ){
u = up[i][u];
v = up[i][v];
}
}
u = up[0][u];
}
L[i] = u;
}
vector <ar<int,2>> rn(q, {0, m + 1}), a;
for ( int i = 0; i < m; i++ ){
a.pb({C[i], P[i]});
}
sort(all(a));
vector <int> us(q);
bool add = true;
while ( true ){
bool finish = true;
vector <vector<int>> qu(m + 1);
for ( int i = 0; i < q; i++ ){
if ( rn[i][0] + 1 < rn[i][1] ){
finish = false;
int md = (rn[i][0] + rn[i][1]) / 2;
qu[md].pb(i);
}
}
Fenw fn1(n), fn2(n);
for ( auto &[C, P]: a ){
fn1.upd(tin[P], 1);
fn1.upd(tout[P] + 1, -1);
}
if ( add ){
for ( int j = 0; j < q; j++ ){
us[j] = fn1.get(tin[S[j]]) + fn1.get(tin[T[j]]) - 2 * fn1.get(tin[L[j]]);
} add = false;
}
for ( int i = 0; i <= m; i++ ){
for ( auto &j: qu[i] ){
int qt = fn2.get(tin[S[j]]) + fn2.get(tin[T[j]]) - 2 * fn2.get(tin[L[j]]);
if ( qt <= Y[j] ){
rn[j][0] = i;
us[j] = fn1.get(tin[S[j]]) + fn1.get(tin[T[j]]) - 2 * fn1.get(tin[L[j]]);
} else rn[j][1] = i;
}
if ( i < m ){
auto [C, P] = a[i];
fn1.upd(tin[P], -1);
fn1.upd(tout[P] + 1, 1);
fn2.upd(tin[P], C);
fn2.upd(tout[P] + 1, -C);
}
}
if ( finish ) break;
}
for ( int i = 0; i < q; i++ ){
cout << max(-1LL, X[i] - us[i]) << ln;
}
cout << '\n';
}
