#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 1000000007
#define INF 1e18
#define fi first
#define se second
#define endl "\n"
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define sz(a) ((int)(a).size())
#define pi 3.14159265359
#define TASKNAME "k"
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
using namespace std;
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
const int MAXN = 1e5 + 9;
struct Station{
int pos_edge;
int fee_silver;
Station(int pos_edge = 0, int fee_silver = 0):
pos_edge(pos_edge), fee_silver(fee_silver){}
};
struct Query{
int start, destination, silver, gold;
Query(int start = 0, int destination = 0, int silver = 0, int gold = 0):
start(start), destination(destination), silver(silver), gold(gold){}
};
int n, m, q;
vector<int> g[MAXN]; ii edge[MAXN];
vector<pair<int, Query>> SetQuery;
vector<Station> SetStation;
map<int, vector<int>> mp;
namespace sub1{
int par[MAXN], depth[MAXN];
void dfs(int u,int p){
for(auto e: g[u]){
int v = edge[e].fi + edge[e].se - u;
if (v == p) continue;
par[v] = e;
depth[v] = depth[u] + 1;
dfs(v, u);
}
}
int getpath(int u,int v,int gold,int silver){
vector<int> path;
int sum = 0;
while(u != v){
// cerr << u << ' ' << v << endl;
if (depth[u] < depth[v]) swap(u, v);
int edge_to_p = par[u];
if (mp[edge_to_p].size() != 0){
for(auto v: mp[edge_to_p]){
path.pb(v);
sum += v;
}
}
u = edge[edge_to_p].fi + edge[edge_to_p].se - u;
}
sum = 0;
if ((int)path.size() > 0) sum = accumulate(path.begin(), path.end(), 0);
else sum = 0;
sort(path.begin(), path.end());
int cnt = 0;
while(sum > silver and path.size() > 0){
cnt++;
sum -= path.back();
path.pop_back();
}
return max(gold - cnt, -1LL);
}
void solve(){
dfs(1, -1);
// for(int i = 1; i <= n; i++){
// cout << depth[i] << ' ' << par[i] << endl;
// }
for(int i = 0; i < q; i++){
int u = SetQuery[i].se.start;
int v = SetQuery[i].se.destination;
int golden = SetQuery[i].se.gold;
int silver = SetQuery[i].se.silver;
cout << getpath(u, v, golden, silver) << endl;
}
}
}
main()
{
fast;
if (fopen(TASKNAME".inp","r")){
freopen(TASKNAME".inp","r",stdin);
freopen(TASKNAME".out","w",stdout);
}
cin >> n >> m >> q;
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
edge[i] = {u, v};
g[u].pb(i);
g[v].pb(i);
}
for(int i = 0; i < m; i++){
int node, fee = 0;
cin >> node >> fee;
SetStation.pb(Station(node, fee));
mp[node].pb(fee);
}
for(int i = 0 ; i < q; i++){
int u, v, silver, gold;
cin >> u >> v >> gold >> silver;
SetQuery.pb({i, Query(u, v, silver, gold)});
}
sub1::solve();
}
