#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;
void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
const int N = 2e5 + 10;
vector <int> g[N], cost[N];
int up[N][30];
int tin[N], tout[N], ch[N], par[N], notch[N];
int timer;
void dfs(int v, int p){
par[v] = p;
tin[v] = timer++;
up[v][0] = p;
for (int i=1; i<=25; ++i)
up[v][i] = up[up[v][i-1]][i-1];
for(auto to : g[v]){
if(to == p)continue;
dfs(to, v);
}
tout[v] = timer++;
}
bool upper (int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
bool upper2 (int a, int b) {
return tin[a] < tin[b] && tout[a] > tout[b];
}
int lca (int a, int b) {
if (upper (a, b)) return a;
if (upper (b, a)) return b;
for (int i=25; i>=0; --i)
if (! upper (up[a][i], b))
a = up[a][i];
return up[a][0];
}
main(){
ios :: sync_with_stdio(0);
cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
vector <pair <int, int> > road = {{-1, -1}};
for(int i = 0; i < n - 1; i++){
int a, b;
cin >> a >> b;
road.pb({a, b});
g[a].pb(b);
g[b].pb(a);
}
dfs(1, 1);
for(int i = 1; i <= n; i++){
int x = road[i].ff, y = road[i].ss;
if(par[x] == y){
ch[i] = x;
notch[i] = y;
}else{
ch[i] = y;
notch[i] = x;
}
}
set <int> st;
vector <int> pref = {0};
int mr = 0;
for(int i = 0; i < m; i++){
int ind, silv;
cin >> ind >> silv;
pref.pb(silv);
st.insert(ind);
mr = ch[ind];
cost[ch[ind]].pb(silv);
}
sort(all(pref));
for(int i = 1; i <= m; i++){
pref[i] += pref[i - 1];
}
pref.pb(2e18);
if((int)st.size() == 1){
for(int i = 0; i < q; i++){
int f, s, gold, silv;
cin >> f >> s >> gold >> silv;
int lc = lca(f, s);
//cout << mr <<"====" << endl;
if(upper2(lc, mr) && upper(mr, f) || upper(mr, s) && upper2(lc, mr)){
int ind = upper_bound(all(pref), silv) - pref.begin();
// cout << ind <<"->"<< m << endl;
if(gold < (m - ind + 1)){
cout <<"-1\n";
}else{
cout << gold - (m - ind + 1) << endl;
}
}else{
cout << gold << endl;
}
}
return 0;
}
//cout << "====" << endl;
for(int i = 0; i < q; i++){
int f, s, gold, silv;
cin >> f >> s >> gold >> silv;
vector <int> c;
int lc = lca(f, s);
while(s != lc){
for(auto x : cost[s]){
c.pb(x);
}
s= par[s];
}
while(f != lc){
for(auto x : cost[f]){
c.pb(x);
}
f = par[f];
}
sort(all(c));
for(auto x : c){
if(silv >= x){
silv -= x;
}else{
gold--;
}
}
if(gold < 0){
cout << "-1\n";
}else{
cout << gold << endl;
}
}
}
