#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
using pii = pair<int, int>;
struct FT{
vector<ll> a;
int n;
FT(int ns){
n = ns;
a.resize(n + 1);
}
ll get(int v){
ll out = 0;
while (v > 0){
out += a[v];
v = (v & (v + 1)) - 1;
}
return out;
}
void upd(int p, int v){
while (p <= n){
a[p] += v;
p |= (p + 1);
}
}
};
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m, q; cin>>n>>m>>q;
vector<pii> g[n + 1];
vector<int> a(n), b(n);
for (int i = 1; i < n; i++){
cin>>a[i]>>b[i];
g[a[i]].push_back({b[i], i});
g[b[i]].push_back({a[i], i});
}
vector<int> p(m + 1), c(m + 1), C(n);
vector<pii> f = {{0, 0}};
for (int i = 1; i <= m; i++){
cin>>p[i]>>c[i];
C[p[i]]++;
f.push_back({c[i], p[i]});
}
sort(f.begin(), f.end());
vector<int> s(q + 1), t(q + 1), x(q + 1), y(q + 1), L(q + 1), R(q + 1);
for (int i = 1; i <= q; i++){
cin>>s[i]>>t[i]>>x[i]>>y[i];
L[i] = 0;
R[i] = m;
}
vector<int> pw[n + 1];
int lg = ceil(log2(n));
for (int i = 1; i <= n; i++){
pw[i].resize(lg + 1);
}
vector<int> tin(n + 1), tout(n + 1), d(n + 1), dd(n + 1);
int timer = 0;
function<void(int, int)> dfs = [&](int v, int pr) -> void{
tin[v] = ++timer;
pw[v][0] = pr;
for (int i = 1; i <= lg; i++){
pw[v][i] = pw[pw[v][i - 1]][i - 1];
}
for (auto [i, j]: g[v]){
if (i == pr) continue;
dd[i] = dd[v] + C[j];
d[i] = d[v] + 1;
dfs(i, v);
}
tout[v] = timer;
};
dfs(1, 1);
auto sub = [&](int x, int y) -> bool{
return (tin[x] <= tin[y] && tout[x] >= tout[y]);
};
auto lca = [&](int x, int y) -> int{
if (sub(x, y)) return x;
if (sub(y, x)) return y;
for (int i = lg; i >= 0; i--){
if (!sub(pw[x][i], y)){
x = pw[x][i];
}
}
return pw[x][0];
};
vector<int> lc(q + 1);
for (int i = 1; i <= q; i++){
lc[i] = lca(s[i], t[i]);
}
auto ff = [&](int x, int y){
if (d[x] > d[y]){
return x;
}
return y;
};
while (true){
bool ind = true;
vector<int> check[m + 1];
for (int i = 1; i <= q; i++){
if (L[i] + 1 < R[i]){
int m = (L[i] + R[i]) / 2;
check[m].push_back(i);
ind = false;
}
}
if (ind) break;
FT T(n);
for (int i = 0; i <= m; i++){
if (i > 0){
auto [v, j] = f[i];
j = ff(a[j], b[j]);
T.upd(tin[j], v);
T.upd(tout[j] + 1, -v);
}
for (int j: check[i]){
ll sum = T.get(tin[s[j]]) + T.get(tin[t[j]]) - 2 * T.get(tin[lc[j]]);
if (sum <= y[j]){
L[j] = i;
}
else {
R[j] = i - 1;
}
}
}
}
vector<int> check[m + 1];
for (int i = 1; i <= q; i++){
check[R[i]].push_back(i);
}
FT T(n);
for (int i = 0; i <= m; i++){
if (i > 0){
auto [v, j] = f[i];
j = ff(a[j], b[j]);
T.upd(tin[j], v);
T.upd(tout[j] + 1, -v);
}
for (int j: check[i]){
ll sum = T.get(tin[s[j]]) + T.get(tin[t[j]]) - 2 * T.get(tin[lc[j]]);
if (sum <= y[j]){
L[j] = R[j];
}
}
}
for (int i = 0; i <= m; i++) check[i].clear();
for (int i = 1; i <= q; i++) check[L[i]].push_back(i);
FT T1(n);
vector<int> cnt(q + 1);
for (int i = 0; i <= m; i++){
if (i > 0){
auto [v, j] = f[i];
j = ff(a[j], b[j]);
T1.upd(tin[j], 1);
T1.upd(tout[j] + 1, -1);
}
for (int j: check[i]){
cnt[j] = T1.get(tin[s[j]]) + T1.get(tin[t[j]]) - 2 * T1.get(tin[lc[j]]);
}
}
for (int i = 1; i <= q; i++){
int len = dd[s[i]] + dd[t[i]] - 2 * dd[lc[i]];
len -= cnt[i];
if (len > x[i]){
cout<<-1<<"\n";
continue;
}
cout<<x[i] - len<<"\n";
}
}
