/*ㅤ∧＿∧
( ･∀･)
( つ┳⊃
ε (_)へ⌒ヽﾌ
( ( ･ω･)
◎―◎ ⊃ ⊃
BePhuongSuperSuwi
From TK4 - CHT
ㅤㅤ／ ⌒＼____
/・ ） \
/ノへ ノ /|
ノ ＼\ |/_/_/*/
#include<bits/stdc++.h>
#define task "main"
#define endl '\n'
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii, ii>
#define base 341
#define MASK(i) (1ll << i)
#define oo 1e18
using namespace std;
const int maxn = 1e5 + 5;
int n, m, test, l[maxn], r[maxn], res[maxn];
int h[maxn], par[maxn], heavy[maxn], head[maxn], pos[maxn], timer, ed[maxn];
vector<ii> v[maxn];
vector<int> query[maxn];
int dfs(int u, int p) {
int max_son = 0, cur = 0;
for (ii e : v[u]) {
int x = e.fi, pos = e.se;
if (x == p) continue;
h[x] = h[u] + 1;
par[x] = u;
ed[pos] = x;
int son = dfs(x, u);
if (max_son < son) {
max_son = son;
heavy[u] = x;
}
cur += son;
}
return cur + 1;
}
void hld(int u, int h) {
head[u] = h;
pos[u] = ++timer;
if (heavy[u]) hld(heavy[u], h);
for (ii e : v[u]) {
int x = e.fi;
if (x != par[u] && x != heavy[u]) {
hld(x, x);
}
}
}
struct HLD {
long long bit[maxn];
void update(int pos, long long v) {
for (int i = pos; i <= n; i += i & -i)
bit[i] += v;
}
long long get(int pos) {
long long res = 0;
for (int i = pos; i ; i -= i & -i)
res += bit[i];
return res;
}
long long getRange(int l, int r) {
return get(r) - get(l - 1);
}
void change(int p, long long val) {
update(pos[ed[p]], val);
}
long long query(int x, int y) {
long long ans = 0;
for (; head[x] != head[y]; y = par[head[y]]) {
if (h[head[x]] > h[head[y]]) swap(x, y);
ans += getRange(pos[head[y]], pos[y]);
}
if (h[x] > h[y]) swap(x, y);
ans += getRange(pos[x] + 1, pos[y]);
return ans;
}
void reset() {
for (int i = 0; i <= n; i++)
bit[i] = 0;
}
} hld1, hld2;
struct pt {
int p;
long long c;
} canh[maxn];
struct tv {
int s, t;
long long x, y;
} q[maxn];
bool ss(pt a, pt b) {
return a.c < b.c;
}
bool check(int id) {
int l = q[id].s, r = q[id].t;
return (hld1.query(l, r) <= q[id].y);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> n >> m >> test;
for (int i = 1; i < n; i++) {
int l, r;
cin >> l >> r;
v[l].pb({r, i}); v[r].pb({l, i});
}
for (int i = 1; i <= m; i++) {
cin >> canh[i].p >> canh[i].c;
}
sort(canh + 1, canh + m + 1, ss);
for (int i = 1; i <= test; i++) {
cin >> q[i].s >> q[i].t >> q[i].x >> q[i].y;
l[i] = 0, r[i] = m, res[i] = -1;
}
dfs(1, -1);
hld(1, 1);
while (true) {
bool ok = false;
for (int i = 1; i <= test; i++) {
if (l[i] > r[i]) continue;
ok = true;
int mid = (l[i] + r[i]) / 2;
query[mid].pb(i);
}
if (!ok) break;
hld1.reset();
hld2.reset();
for (int mid = 0; mid <= m; mid++) {
if (mid > 0) {
int p = canh[mid].p;
long long val = canh[mid].c;
hld1.change(p, val);
hld2.change(p, 1);
}
for (auto id : query[mid]) {
if (check(id)) {
res[id] = hld2.query(q[id].s, q[id].t);
l[id] = mid + 1;
} else r[id] = mid - 1;
}
query[mid].clear();
}
}
hld2.reset();
for (int i = 1; i <= m; i++) {
int p = canh[i].p;
hld2.change(p, 1);
}
for (int i = 1; i <= test; i++) {
int l = q[i].s, r = q[i].t;
cout << max(-1ll, q[i].x - (hld2.query(l, r) - res[i])) << endl;
}
}
