#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<ll, ll>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
struct el {
ll a;
ll b;
ll x;
ll y;
};
const ll MAXN = 100 * 1000 + 17;
const ll MAXQ = 100 * 1000 + 17;
const ll MAXLOG = 20;
const ll K = 20;
vector<ll> graf[MAXN];
ll pre[MAXN];
ll post[MAXN];
ll st[8 * MAXN];
vector<pair<ll, ll>> bram;
ll tp[MAXQ];
ll tk[MAXQ];
ll tsr[MAXQ];
bool tok[MAXQ];
ll tw[MAXQ];
el zap[MAXQ];
vector<ll> jakie[MAXN];
vector<pii> kraw;
ll pam[MAXN][MAXLOG];
ll lev[MAXN];
ll wyn[MAXQ];
ll cnt = 0;
void DFS (ll v, ll o) {
pre[v] = cnt;
cnt ++;
for (auto x : graf[v]) {
if (x != o) {
DFS(x, v);
}
}
post[v] = cnt;
cnt ++;
}
void aktualizuj(ll p, ll k, ll a, ll b, ll w, ll i) {
if (p > b || k < a) {
return;
}
if (a <= p && k <= b) {
st[i] += w;
return;
}
ll sr = (p + k)/2;
aktualizuj(p, sr, a, b, w, i * 2);
aktualizuj(sr + 1, k, a, b, w, i * 2 + 1);
}
ll zapytanie(ll p, ll k, ll ind, ll i) {
if (p == k && k == ind) {
return st[i];
}
ll sr = (p + k)/2;
ll a = 0;
if (ind <= sr) {
a = zapytanie(p, sr, ind, i * 2);
} else {
a = zapytanie(sr + 1, k, ind, i * 2 + 1);
}
return (a + st[i]);
}
void DFS2(ll v, ll p) {
pam[v][0] = p;
for (ll i = 1; i < MAXLOG; i ++) {
pam[v][i] = pam[pam[v][i - 1]][i - 1];
}
for (auto x : graf[v]) {
if (x != p) {
lev[x] = lev[v] + 1;
DFS2(x, v);
}
}
}
ll LCA(ll a, ll b) {
if (lev[a] < lev[b]) {
swap(a, b);
}
ll pot = (1 << (MAXLOG - 1));
for (ll i = MAXLOG - 1; i >= 0; i--) {
if (lev[a] - pot >= lev[b]) {
a = pam[a][i];
}
pot /= 2;
}
if (a == b) {
return a;
}
for (ll i = MAXLOG - 1; i >= 0; i--) {
if (pam[a][i] != pam[b][i]) {
a = pam[a][i];
b = pam[b][i];
}
}
return pam[a][0];
}
bool comp (pii a, pii b) {
return (a.nd < b.nd);
}
int main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll n, m, q;
cin >> n >> m >> q;
ll a, b;
kraw.pb({0, 0});
for (ll i = 0; i < n - 1; i ++) {
cin >> a >> b;
graf[a].pb(b);
graf[b].pb(a);
kraw.pb({a, b});
}
ll p;
ll c;
bram.pb({0, 0});
for (ll i = 1; i <= m; i ++) {
cin >> p >> c;
bram.pb({p, c});
}
sort(bram.begin(), bram.end(), comp);
for (auto x : bram) {
//cout << x.nd << "\n";
}
for (ll i = 0; i < q; i ++) {
cin >> zap[i].a >> zap[i].b >> zap[i].x >> zap[i].y;
}
DFS(1, 1);
DFS2(1, 1);
//cout << LCA(3, 5) << "\n";
ll nr = 0;
for (auto x : kraw) {
if (pre[x.nd] > pre[x.st]) {
swap(kraw[nr].st, kraw[nr].nd);
}
nr ++;
}
for (ll i = 0; i < q; i ++) {
tk[i] = m;
}
for (ll zz = 0; zz < K; zz ++) {
for (ll i = 0; i <= m; i ++) {
jakie[i].clear();
}
for (ll i = 0; i < q; i ++) {
tok[i] = false;
tsr[i] = (tp[i] + tk[i])/ 2;
if (tp[i] <= tk[i]) {
jakie[tsr[i]].pb(i);
} else {
tsr[i] = tw[i];
}
}
for (ll i = 0; i <= m; i ++) {
ll v = kraw[bram[i].st].st;
//cout << i << ": " << v << "\n";
if (i != 0) {
aktualizuj(0, 2 * n, pre[v], post[v], bram[i].nd, 1);
}
for (auto x : jakie[i]) {
ll s1 = zapytanie(0, 2 * n, pre[zap[x].a], 1);
ll s2 = zapytanie(0, 2 * n, pre[zap[x].b], 1);
ll s3 = zapytanie(0, 2 * n, pre[LCA(zap[x].b, zap[x].a)], 1);
//cout << x << "\n";
//cout << i << " " << s1 << " " << s2 << " " << s3 << "\n";
//cout << tw[x] << "\n";
//cout << s1 + s2 - 2LL * s3 << "?" << zap[x].y << "\n";
if ((s1 + s2 - 2LL * s3) <= zap[x].y) {
tok[x] = true;
//cout << "ha\n";
}
//cout << tok[x] << "\n";
//cout << "\n";
}
}
for (ll i = 0; i < q; i ++) {
if (tp[i] <= tk[i]) {
if (tok[i]) {
tw[i] = tsr[i];
tp[i] = tsr[i] + 1;
} else {
tk[i] = tsr[i] - 1;
}
}
}
for (ll i = 0; i < 8 * n; i ++) {
st[i] = 0;
}
}
//cout << tw[0] << "\n";
for (ll i = 0; i <= m + 1; i ++) {
jakie[i].clear();
}
for (ll i = 0; i < q; i ++) {
jakie[tw[i] + 1].pb(i);
}
for (ll i = m + 1; i >= 1; i --) {
if (i != m + 1) {
ll v = kraw[bram[i].st].st;
aktualizuj(0, 2 * n, pre[v], post[v], 1, 1);
}
for (auto x : jakie[i]) {
ll s1 = zapytanie(0, 2 * n, pre[zap[x].a], 1);
ll s2 = zapytanie(0, 2 * n, pre[zap[x].b], 1);
ll s3 = zapytanie(0, 2 * n, pre[LCA(zap[x].b, zap[x].a)], 1);
wyn[x] = max(-1LL, zap[x].x - (s1 + s2 - 2LL * s3));
}
}
for (ll i = 0; i < q; i ++) {
cout << wyn[i] << "\n";
}
return 0;
}
