#include<bits/stdc++.h>
#define pii pair<int,int>
#define fi first
#define se second
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define sz(v) (int)(v).size()
#define endl "\n"
#define dbg(x) "[" #x " = " << (x) << "]"
using namespace std;
template<class T> bool minimize(T& a, T b){
if(a > b) return a = b, true;
return false;
}
template<class T> bool maximize(T& a, T b){
if(a < b) return a = b, true;
return false;
}
typedef long long ll;
void fastIO(){
ios_base::sync_with_stdio(NULL); cin.tie(0);
#ifdef LOCAL
freopen("task.INP", "r", stdin);
freopen("task.OUT", "w", stdout);
#endif // LOCAL
}
const int MAX = 2e5 + 5;
const int lg = 16;
struct FenwickTree{
int n;
vector<ll> bit;
FenwickTree(int n) : n(n), bit(n + 5, 0) {}
void update(int idx, ll v){
for(;idx <= n; idx += (idx & (-idx))) bit[idx] += v;
}
ll get(int idx){ll res = 0;
for(;idx; idx -= (idx & (-idx))) res += bit[idx];
return res;
}
void reset(){
for(int i = 1; i <= n; i++) bit[i] = 0;
}
};
int n, m, q;
int eu[MAX], ev[MAX];
vector<int> adj[MAX];
pii tax[MAX];
int h[MAX];
int par[MAX][lg+1];
int tin[MAX], tout[MAX], timer;
pair<ll, ll> query[MAX], have[MAX];
ll ans[MAX];
void dfs(int u){
tin[u] = ++timer;
for(int v : adj[u]) if(v != par[u][0]){
h[v] = h[u] + 1;
par[v][0] = u;
for(int j = 1; j <= lg; j++) par[v][j] = par[par[v][j-1]][j-1];
dfs(v);
}
tout[u] = timer;
}
int lca(int u, int v){
if(h[u] < h[v]) swap(u, v);
for(int j = lg; j >= 0; j--) if(h[u] - (1 << j) >= h[v]){
u = par[u][j];
}
if(u == v) return u;
for(int j = lg; j >= 0; j--){
if(par[u][j] != par[v][j]){
u = par[u][j];
v = par[v][j];
}
}
return par[u][0];
}
int l[MAX], r[MAX];
vector<int> candidates[MAX];
signed main(){
fastIO();
cin >> n >> m >> q;
for(int i = 1; i < n; i++){
cin >> eu[i] >> ev[i];
adj[eu[i]].push_back(ev[i]);
adj[ev[i]].push_back(eu[i]);
}
for(int i = 1; i <= m; i++){
cin >> tax[i].se >> tax[i].fi;
}
for(int i = 1; i <= q; i++){
cin >> query[i].fi >> query[i].se >> have[i].fi >> have[i].se;
l[i] = 0;
r[i] = m;
ans[i] = -1;
}
dfs(1);
for(int i = 1; i < n; i++){
if(h[eu[i]] > h[ev[i]]) swap(eu[i], ev[i]);
}
sort(tax + 1, tax + 1 + m);
for(int i = 1; i <= m; i++) swap(tax[i].fi, tax[i].se);
FenwickTree bit(n), cnt(n);
while(true){
bool any = false;
for(int i = 1; i <= q; i++){
if(l[i] > r[i]) continue;
candidates[l[i] + r[i] >> 1].push_back(i);
any = true;
}
if(!any) break;
for(int i = 1; i <= m; i++){
int id = tax[i].fi;
cnt.update(tin[ev[id]], 1);
cnt.update(tout[ev[id]] + 1, -1);
}
for(int i = 0; i <= m; i++){
if(i){
int id = tax[i].fi;
int cost = tax[i].se;
bit.update(tin[ev[id]], +cost);
bit.update(tout[ev[id]] + 1, -cost);
cnt.update(tin[ev[id]], -1);
cnt.update(tout[ev[id]] + 1, +1);
}
auto get_dist = [&](int u, int v) -> ll{
return bit.get(tin[u]) + bit.get(tin[v]) - 2LL*bit.get(tin[lca(u,v)]);
};
auto get_cnt = [&](int u, int v) -> ll{
return cnt.get(tin[u]) + cnt.get(tin[v]) - 2LL*cnt.get(tin[lca(u,v)]);
};
while(sz(candidates[i])){
int id = candidates[i].back();
candidates[i].pop_back();
if(get_dist(query[id].fi, query[id].se) <= have[id].se){
ans[id] = get_cnt(query[id].fi, query[id].se);
l[id] = i + 1;
}
else r[id] = i - 1;
}
}
bit.reset();
cnt.reset();
}
for(int i = 1; i <= q; i++){
int res = ans[i];
if(res != -1) res = max(-1LL, have[i].fi - ans[i]);
cout << res << endl;
}
}
