#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int, int>
using namespace std;
const int N = 1e5 + 5;
int n, m, q;
vector<int> adj[N];
int par[N][20], in[N], out[N], depth[N];
pii E[N], Q[N];
int cnt = 0;
int S[N], T[N], X[N], Lca[N];
long long Y[N];
int L[N], R[N];
vector<int> id[N];
int ans[N];
struct BIT{
long long tree[N];
void reset() {
memset(tree, 0, sizeof(tree));
}
void update(int i, int val) {
for(; i <= n; i += i & -i) tree[i] += val;
}
long long get(int i) {
long long res = 0;
for(; i > 0; i -= i & -i) res += tree[i];
return res;
}
};
BIT BIT1, BIT2;
void dfs(int u) {
in[u] = ++cnt;
for(auto v : adj[u]) {
if(v == par[u][0]) continue;
par[v][0] = u;
depth[v] = depth[u] + 1;
for(int i = 1; i <= 18; i++) par[v][i] = par[par[v][i - 1]][i - 1];
dfs(v);
}
out[u] = cnt;
}
int lca(int u, int v) {
if(depth[u] < depth[v]) swap(u, v);
int len = depth[u] - depth[v];
for(int i = 18; i >= 0; i--) if((len >> i) & 1) u = par[u][i];
if(u == v) return u;
for(int i = 18; i >= 0; i--) if(par[u][i] != par[v][i]) u = par[u][i], v = par[v][i];
return par[u][0];
}
void Solve() {
cin >> n >> m >> q;
for(int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
E[i] = {u, v};
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1);
for(int i = 1; i < n; i++) if(lca(E[i].fi, E[i].se) == E[i].se) swap(E[i].fi, E[i].se);
for(int i = 1; i <= m; i++) {
int x, y; cin >> x >> y;
Q[i] = {y, x};
}
sort(Q + 1, Q + m + 1);
for(int i = 1; i <= q; i++) {
cin >> S[i] >> T[i] >> X[i] >> Y[i];
Lca[i] = lca(S[i], T[i]);
L[i] = 0;
R[i] = m;
}
while(true) {
bool ok = true;
for(int i = 1; i <= m; i++) id[i].clear();
for(int i = 1; i <= q; i++) {
// cout << i << " " << L[i] << " " << R[i] << '\n';
if(L[i] <= R[i]) {
int mid = (L[i] + R[i]) / 2;
id[mid].push_back(i);
ok = false;
}
}
if(ok) break;
BIT1.reset();
BIT2.reset();
for(int i = 1; i <= m; i++) {
int u = E[Q[i].se].se;
BIT1.update(in[u], 1);
BIT1.update(out[u] + 1, -1);
}
for(int i = 0; i <= m + 1; i++) {
int u = E[Q[i].se].se;
if(i >= 1 && i <= m) {
BIT1.update(in[u], -1);
BIT1.update(out[u] + 1, 1);
BIT2.update(in[u], Q[i].fi);
BIT2.update(out[u] + 1, -Q[i].fi);
}
for(auto x : id[i]) {
long long sum = BIT2.get(in[S[x]]) + BIT2.get(in[T[x]]) - 2 * BIT2.get(in[Lca[x]]);
if(sum <= Y[x]) {
ans[x] = BIT1.get(in[S[x]]) + BIT1.get(in[T[x]]) - 2 * BIT1.get(in[Lca[x]]);
L[x] = i + 1;
}
else R[x] = i - 1;
}
}
}
for(int i = 1; i <= q; i++) {
cout << max(-1, X[i] - ans[i]) << '\n';
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
Solve();
}
