#include <bits/stdc++.h>
#define all(v) v.begin(),v.end()
#define pb push_back
#define ll long long
using namespace std;
struct segmentTree {
vector<ll> tree;
void init(int n) {
tree.clear();
tree.resize(1 << (int)ceil(log2(n)) + 1);
}
void update(int lx, int rx, ll v, int l, int r, int n) {
if (r < lx || rx < l)
return;
if (lx <= l && r <= rx) {
tree[n] += v;
return;
}
int m = (l + r) >> 1;
update(lx, rx, v, l, m, n << 1);
update(lx, rx, v, m + 1, r, n << 1 | 1);
}
ll query(int x, int l, int r, int n) {
if (r < x || x < l)
return 0;
if (l == r)
return tree[n];
int m = (l + r) >> 1;
return query(x, l, m, n << 1) + query(x, m + 1, r, n << 1 | 1) + tree[n];
}
};
struct query {
int s, t;
ll x, y;
};
int N, M, Q;
vector<int> Adj[100000];
pair<int, int> Edges[100000];
pair<ll, int> CP[100000];
query Queries[100000];
int In[100000], Out[100000];
int Par[17][100000];
int Depth[100000];
int QL[100000], QR[100000], QX[100000];
segmentTree ST;
ll Ans[100000];
int dfs(int v, int par, int cur) {
In[v] = ++cur;
for (int i : Adj[v]) {
if (i != par)
cur = dfs(i, v, cur);
}
return Out[In[v]] = cur;
}
int getLCA(int u, int v) {
if (Depth[u] > Depth[v])
swap(u, v);
for (int i = 0, t = Depth[v] - Depth[u]; t; i++, t >>= 1) {
if (t & 1)
v = Par[i][v];
}
if (u == v)
return u;
for (int i = 16; i >= 0; i--) {
if (Par[i][u] != Par[i][v]) {
u = Par[i][u];
v = Par[i][v];
}
}
return Par[0][u];
}
ll pathQuery(int u, int v) {
int lca = getLCA(u, v);
return ST.query(u, 0, N - 1, 1) + ST.query(v, 0, N - 1, 1) - 2 * ST.query(lca, 0, N - 1, 1);
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> M >> Q;
for (int i = 0; i < N - 1; i++) {
int a, b;
cin >> a >> b;
Edges[i] = { --a,--b };
Adj[a].pb(b);
Adj[b].pb(a);
}
for (int i = 0; i < M; i++) {
int p;
ll c;
cin >> p >> c;
CP[i] = { c,--p };
}
sort(CP, CP + M);
for (int i = 0; i < Q; i++) {
int s, t;
ll x, y;
cin >> s >> t >> x >> y;
Queries[i] = { --s,--t,x,y };
}
dfs(0, -1, -1);
for (int i = 0; i < N - 1; i++) {
pair<int, int>& cur = Edges[i];
cur.first = In[cur.first];
cur.second = In[cur.second];
if (cur.first > cur.second)
swap(cur.first, cur.second);
Par[0][cur.second] = cur.first;
}
for (int i = 1; i < N; i++)
Depth[i] = Depth[Par[0][i]] + 1;
for (int i = 0; i < Q; i++) {
query& cur = Queries[i];
cur.s = In[cur.s];
cur.t = In[cur.t];
}
for (int i = 1; i < 17; i++) {
for (int j = 0; j < N; j++)
Par[i][j] = Par[i - 1][Par[i - 1][j]];
}
fill(QR, QR + Q, M);
while (1) {
bool flag = true;
vector<pair<int, int>> v;
for (int i = 0; i < Q; i++) {
if (QL[i] <= QR[i]) {
flag = false;
v.pb({ (QL[i] + QR[i]) >> 1,i });
}
}
if (flag)
break;
sort(all(v));
ST.init(N);
for (int i = 0, j = 0; i <= M; i++) {
if (i) {
int cur = Edges[CP[i - 1].second].second;
ll c = CP[i - 1].first;
ST.update(cur, Out[cur], c, 0, N - 1, 1);
}
while (j < (int)v.size() && v[j].first == i) {
int cur = v[j++].second;
if (pathQuery(Queries[cur].s, Queries[cur].t) <= Queries[cur].y) {
QX[cur] = i;
QL[cur] = i + 1;
}
else
QR[cur] = i - 1;
}
}
}
vector<pair<int, int>> v;
for (int i = 0; i < Q; i++)
v.push_back({ QX[i],i });
sort(all(v));
ST.init(N);
for (int i = 0, j = 0; i <= M; i++) {
if (i) {
int cur = Edges[CP[i - 1].second].second;
ST.update(cur, Out[cur], 1, 0, N - 1, 1);
}
while (j < (int)v.size() && v[j].first == i) {
int cur = v[j++].second;
Ans[cur] = pathQuery(Queries[cur].s, Queries[cur].t);
}
}
for (int i = 0; i < Q; i++)
cout << max(Queries[i].x - pathQuery(Queries[i].s, Queries[i].t) + Ans[i], (ll)-1) << "\n";
return 0;
}
