#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define X first
#define Y second
const int MXN = 1e5+5, LOG = 17;
int n;
template<typename T> struct Fen {
T fen[MXN];
inline void upd(int s, int e, T x) {
for(++s; s<=n; s+=s&-s) fen[s] += x;
for(++e; e<=n; e+=e&-e) fen[e] -= x;
}
inline T get(int p) {
T res=0;
for(++p; p; p-=p&-p) res += fen[p];
return res;
}
};
Fen<ll> f0;
Fen<int> f1;
vector<int> g[MXN];
int A[MXN], B[MXN], par[MXN], jp[MXN], h[MXN], stt[MXN], fnt[MXN], timer;
void dfs(int v) {
jp[v] = h[jp[jp[par[v]]]] - h[jp[par[v]]] == h[jp[par[v]]] - h[par[v]] ? jp[jp[par[v]]] : par[v];
stt[v] = timer++;
for(int u : g[v])
if(u!=par[v])
par[u] = v,
h[u] = h[v]+1,
dfs(u);
fnt[v] = timer;
}
inline int jump(int v, int d) {
if(d==h[v]) return v;
while(h[par[v]]>d)
v = h[jp[v]]>d ? jp[v] : par[v];
return par[v];
}
inline int LCA(int u, int v) {
if(h[u]<h[v]) swap(u, v);
u = jump(u, h[v]);
if(u==v) return u;
while(par[u]!=par[v])
if(jp[u]==jp[v]) u=par[u], v=par[v];
else u=jp[u], v=jp[v];
return par[u];
}
inline void upd(int v, ll x) {
f0.upd(stt[v], fnt[v], x);
f1.upd(stt[v], fnt[v], 1);
}
inline pair<ll, int> get(int u, int v) {
int lca = LCA(u, v);
return {
f0.get(stt[u]) + f0.get(stt[v]) - 2*f0.get(stt[lca]),
f1.get(stt[u]) + f1.get(stt[v]) - 2*f1.get(stt[lca])
};
}
inline void clear() {
memset(f0.fen, 0, sizeof(f0.fen));
memset(f1.fen, 0, sizeof(f1.fen));
}
int m, q, P[MXN], C[MXN], sq[MXN], tq[MXN], xq[MXN], yq[MXN], L[MXN], R[MXN], ans[MXN], ord[MXN];
vector<int> vec[MXN];
int32_t main() {
cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
cin >> n >> m >> q;
for(int i=1; i<=n-1; i++) {
cin >> A[i] >> B[i];
g[A[i]].push_back(B[i]);
g[B[i]].push_back(A[i]);
}
par[0] = 0;
dfs(1);
clear();
for(int i=1; i<=m; i++) {
cin >> P[i] >> C[i];
P[i] = A[P[i]]==par[B[P[i]]] ? B[P[i]] : A[P[i]];
ord[i] = i;
upd(P[i], 0);
}
sort(ord+1, ord+m+1, [&](int i, int j) {
return C[i] < C[j];
});
for(int i=1; i<=q; i++) {
cin >> sq[i] >> tq[i] >> xq[i] >> yq[i];
L[i] = 0, R[i] = m+1;
ans[i] = get(sq[i], tq[i]).Y;
}
while(1) {
clear();
for(int i=1; i<=m; i++) vec[i].clear();
bool fnd = 0;
for(int i=1; i<=q; i++)
if(R[i]-L[i]>1) {
fnd = 1;
vec[(L[i]+R[i])>>1].push_back(i);
}
if(!fnd) break;
for(int i=1; i<=m; i++) {
upd(P[ord[i]], C[ord[i]]);
for(int j : vec[i])
(get(sq[j], tq[j]).X<=yq[j] ? L[j] : R[j]) = i;
}
}
clear();
for(int i=1; i<=m; i++) vec[i].clear();
for(int i=1; i<=q; i++) vec[L[i]].push_back(i);
for(int i=0; i<=m; i++) {
if(i) upd(P[ord[i]], 0);
for(int j : vec[i]) {
int cnt = get(sq[j], tq[j]).Y;
ans[j] = max(-1, xq[j] - (ans[j]-cnt));
}
}
for(int i=1; i<=q; i++) cout << ans[i] << '\n';
return 0;
}
