#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 110000;
const int LOGN = 20;
struct edge {int u, v;};
struct ch {int v, c;};
struct route {int s, t, lca, x, y, lans, rans, id;};
struct fenwick {
vector<int> ff; int n;
fenwick() {}
fenwick(int n) {
this->n = n;
ff = vector<int>(n + 1, 0);
}
void upd(int k, int x) {
for (; k <= n; k += k & -k)
ff[k] += x;
}
int get(int k) {
int ans = 0;
for (; k >= 1; k -= k & -k)
ans += ff[k];
return ans;
}
};
int n, m, q, dd[N], jj[N][LOGN], tin[N], tout[N], tcur = 0, ans[N];
edge ee[N];
ch cc[N];
vector<route> rr;
vector<int> g[N];
fenwick cnt;
void dfs(int v, int p = -1) {
dd[v] = (p == -1 ? 0 : dd[p] + 1);
jj[v][0] = (p == -1 ? v : p);
for (int k = 1; k < LOGN; k++)
jj[v][k] = jj[jj[v][k - 1]][k - 1];
tin[v] = ++tcur;
for (int u : g[v]) if (u != p)
dfs(u, v);
tout[v] = tcur;
}
int lca(int u, int v) {
if (dd[u] < dd[v])
swap(u, v);
for (int k = LOGN - 1; k >= 0; k--)
if (dd[u] - (1 << k) >= dd[v])
u = jj[u][k];
if (u == v) return u;
for (int k = LOGN - 1; k >= 0; k--)
if (jj[u][k] != jj[v][k]) {
u = jj[u][k];
v = jj[v][k];
}
return jj[u][0];
}
void upd(int v, int c) {
cnt.upd(tin[v], c);
if (tout[v] < n)
cnt.upd(tout[v] + 1, -c);
}
int sum(route rt) {
return cnt.get(tin[rt.s]) + cnt.get(tin[rt.t]) - 2 * cnt.get(tin[rt.lca]);
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n >> m >> q;
for (int i = 1; i <= n - 1; i++) {
cin >> ee[i].u >> ee[i].v;
g[ee[i].u].push_back(ee[i].v);
g[ee[i].v].push_back(ee[i].u);
}
for (int i = 1; i <= m; i++)
cin >> cc[i].v >> cc[i].c;
rr = vector<route>(q);
for (int i = 0; i < q; i++)
cin >> rr[i].s >> rr[i].t >> rr[i].x >> rr[i].y;
dfs(1);
for (int i = 1; i <= m; i++) {
int u = ee[cc[i].v].u;
int v = ee[cc[i].v].v;
if (dd[u] < dd[v])
cc[i].v = v;
else
cc[i].v = u;
}
sort(cc + 1, cc + m + 1, [&](auto c1, auto c2) {return c1.c < c2.c;});
for (int i = 0; i < q; i++) {
rr[i].id = i + 1;
rr[i].lans = 0;
rr[i].rans = m;
rr[i].lca = lca(rr[i].s, rr[i].t);
}
while (true) {
bool good = true;
vector<route> nr, cur;
int ptr = 1;
cnt = fenwick(n);
for (int i = 0; i < q; i++) {
cur.push_back(rr[i]);
if (i == q - 1 || rr[i].lans != rr[i + 1].lans) {
int tl = rr[i].lans;
int tr = rr[i].rans;
if (tl == tr) {
for (auto &rt : cur)
nr.push_back(rt);
} else {
int mid = (tl + tr) / 2 + 1;
while (ptr <= mid) {
upd(cc[ptr].v, cc[ptr].c);
ptr++;
}
for (auto &rt : cur)
rt.lans = sum(rt);
for (auto rt : cur)
if (rt.y < rt.lans) {
rt.lans = tl;
rt.rans = mid - 1;
if (tl != mid - 1) good = false;
nr.push_back(rt);
}
for (auto rt : cur)
if (rt.y >= rt.lans) {
rt.lans = mid;
rt.rans = tr;
if (mid != tr) good = false;
nr.push_back(rt);
}
}
cur.clear();
}
}
rr = nr;
if (good) break;
}
cnt = fenwick(n);
int ptr = m;
for (int i = q - 1; i >= 0; i--) {
while (ptr > rr[i].lans) {
upd(cc[ptr].v, 1);
ptr--;
}
rr[i].x -= sum(rr[i]);
}
for (auto rt : rr)
ans[rt.id] = max(rt.x, -1ll);
for (int i = 1; i <= q; i++)
cout << ans[i] << '\n';
}
