#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
#define sz(a) (int)((a).size())
#define all(a) (a).begin(), (a).end()
#define uni(a) sort(all(a)), (a).resize(unique(all(a)) - (a).begin())
typedef pair <int, int> ii;
const int N = 1e5 + 20;
int n, m, q, timer;
int in[N], ou[N], node[N], depth[N], up[N][20], ans[N], l[N], r[N];
vector <int> graph[N];
vector <ii> arr, ask;
ii edge[N];
ll f[N], sum[N];
void dfs(int u = 1, int p = -1) {
in[u] = ++timer; node[timer] = u;
for (int i = 1; i <= 17; i++) up[u][i] = up[up[u][i - 1]][i - 1];
for (int i = 0; i < sz(graph[u]); i++) if (graph[u][i] != p) {
int v = graph[u][i];
depth[v] = depth[u] + 1;
up[v][0] = u;
dfs(v, u);
}
ou[u] = timer;
}
int lca(int u, int v) {
if (depth[u] < depth[v])
swap(u, v);
int k = depth[u] - depth[v];
for (int i = 0; i <= 17; i++)
if (k & (1 << i)) {
u = up[u][i];
}
if (u == v) return u;
for (int i = 17; i >= 0; i--)
if (up[u][i] != up[v][i]) {
u = up[u][i];
v = up[v][i];
}
return up[u][0];
}
void upd(int x, ll y) {
for (int i = x; i <= n + 10; i += i & (-i))
f[i] += y;
}
ll get(int x) {
ll s = 0;
for (int i = x; i >= 1; i -= i & (-i))
s += f[i];
return s;
}
struct qry {
ll x, y, s, t;
} qr[N];
void solve() {
cin >> n >> m >> q;
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v;
graph[u].push_back(v);
graph[v].push_back(u);
edge[i] = {u, v};
}
for (int i = 1; i <= m; i++) {
int x, y;
cin >> x >> y;
arr.push_back({y, x});
}
dfs();
for (int i = 1; i < n; i++) {
if (depth[edge[i].s] < depth[edge[i].f])
swap(edge[i].f, edge[i].s);
}
for (int i = 0; i < sz(arr); i++) {
arr[i].s = edge[arr[i].s].s;
}
sort(all(arr));
for (int i = 1; i <= q; i++) {
cin >> qr[i].s >> qr[i].t >> qr[i].x >> qr[i].y;
l[i] = 0, r[i] = m;
ans[i] = -1;
}
while (1) {
ask.clear();
for (int i = 1; i <= q; i++) {
if (l[i] <= r[i]) {
ask.push_back({(l[i] + r[i]) / 2, i});
}
}
sort(all(ask));
if (sz(ask) == 0)
break;
for (int i = 1; i <= n + 10; i++) {
f[i] = 0;
}
for (int i = 0, j = 0; i < sz(ask); i++) {
while (j < sz(arr) && j <= ask[i].f) {
upd(in[arr[j].s], arr[j].f);
upd(ou[arr[j].s] + 1, -arr[j].f);
j++;
}
int u = qr[ask[i].s].s, v = qr[ask[i].s].t;
int p = lca(u, v);
ll su = get(in[u]);
ll sv = get(in[v]);
ll sp = get(in[p]);
sum[ask[i].s] = su + sv - 2 * sp;
}
for (int i = 1; i <= q; i++) {
if (sum[i] <= qr[i].y) {
ans[i] = (l[i] + r[i]) / 2;
l[i] = (l[i] + r[i]) / 2 + 1;
} else {
r[i] = (l[i] + r[i]) / 2 - 1;
}
}
}
for (int i = 1; i <= n + 10; i++) {
f[i] = 0;
}
ask.clear();
for (int i = 1; i <= q; i++) {
ask.push_back({ans[i], i});
}
sort(all(ask));
for (int i = sz(ask) - 1, j = sz(arr) - 1; i >= 0; i--) {
while (j >= 0 && j > ask[i].f) {
upd(in[arr[j].s], 1);
upd(ou[arr[j].s] + 1, -1);
j--;
}
int u = qr[ask[i].s].s, v = qr[ask[i].s].t;
int p = lca(u, v);
ll su = get(in[u]);
ll sv = get(in[v]);
ll sp = get(in[p]);
ans[ask[i].s] = su + sv - 2 * sp;
}
for (int i = 1; i <= q; i++) {
if (ans[i] <= qr[i].x) {
cout << qr[i].x - ans[i] << '\n';
} else {
cout << -1 << '\n';
}
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("a.inp", "r", stdin);
// freopen("a.out", "w", stdout);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
return 0;
}
