#include <bits/stdc++.h>
#define ll long long
#define endl "\n"
using namespace std;
struct Fensum{
ll len=1;
vector<ll> tree;
Fensum(int l){
len=l+1;
tree=vector<ll>(len+1,0);
}
void update(int idx,ll v){
idx++;
while(idx<=len){
tree[idx]+=v;
idx+=(idx&-idx);
}
}
ll query(int idx){
idx++;
ll res = 0;
while(idx>=1){
res += tree[idx];
idx-=(idx&-idx);
}
return res;
}
};
const int LOG = 20;
const int mxN = 100001;
int N,M,Q;
vector<int> adj[mxN];
vector<pair<int,int>> edges;
vector<int> depth(mxN,0);
vector<int> sub_sz(mxN,1);
vector<int> in(mxN,0);
vector<int> ot(mxN,0);
vector<int> parent(mxN,-1);
int jump[mxN][LOG];
int timer;
void dfs(int node,int p=-1){
parent[node]=p;
in[node]=timer++;
for(int u : adj[node]){
if(u==p)
continue;
depth[u]=depth[node]+1;
dfs(u,node);
sub_sz[node]+=sub_sz[u];
}
ot[node]=timer++;
}
ll get_sum(int node,int parent,Fensum &fen){
return fen.query(in[node])-fen.query(in[parent]);
}
void activate(int node,ll v,Fensum &fen){
fen.update(in[node],v);
fen.update(ot[node],-v);
}
void init_lca(){
for(int i=0;i<mxN;i++){
for(int e=0;e<LOG;e++){
jump[i][e]=-1;
}
}
for(int u=0;u<mxN;u++){
jump[u][0]=parent[u];
}
for(int e=1;e<LOG;e++){
for(int u=0;u<mxN;u++){
if(jump[u][e-1]!=-1)
jump[u][e]=jump[jump[u][e-1]][e-1];
}
}
}
int lca(int a,int b){
if(depth[a]<depth[b])
swap(a,b);
int k = depth[a]-depth[b];
for(int e=LOG-1;e>=0;e--){
if((1<<e)&k){
a=jump[a][e];
}
}
if(a==b)
return a;
for(int e=LOG-1;e>=0;e--){
int u = jump[a][e],v = jump[b][e];
if(u!=v){
a=u,b=v;
}
}
return parent[a];
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
timer=0;
cin >> N >> M >> Q;
for(int i=0;i<N-1;i++){
int u,v;
cin >> u >> v;
u--,v--;
adj[u].push_back(v);
adj[v].push_back(u);
edges.push_back(make_pair(u,v));
}
dfs(0);
for(int i=0;i<N-1;i++){
int u=edges[i].first,v=edges[i].second;
if(depth[u]>depth[v])
swap(edges[i].first,edges[i].second);
}
vector<pair<ll,int>> op;//cost,node
vector<int> nbop(N,0);
for(int i=0;i<M;i++){
ll idx_arr,cost;
cin >> idx_arr >> cost;
idx_arr--;
op.push_back(make_pair(cost,edges[idx_arr].second));
}
sort(op.begin(),op.end());
vector<ll> s(Q),e(Q),gold(Q),silver(Q);
for(int i =0;i<Q;i++){
cin >> s[i] >> e[i] >> gold[i] >> silver[i];
s[i]--,e[i]--;
}
init_lca();
vector<int> lo(Q,0);
vector<int> hi(Q,M);
for(int _=0;_<20;_++){
Fensum fen_act(3*N+1);
vector<pair<int,int>> mid;
for(int q=0;q<Q;q++){
mid.push_back(make_pair(lo[q]+(hi[q]-lo[q]+1)/2,q));
}
sort(mid.rbegin(),mid.rend());
for(int k=0;k<=M;k++){//k:=nb activé
if(k>0)
activate(op[k-1].second,op[k-1].first,fen_act);
while(mid.size()>0&&mid.back().first==k){
int q = mid.back().second;
int u = s[q],v = e[q];
if(depth[u]>depth[v])
swap(u,v);
int z = lca(u,v);
ll cost = get_sum(v,z,fen_act);
if(z!=u)//different path
cost+=get_sum(u,z,fen_act);
if(cost<=silver[q])
lo[q]=k;
else
hi[q]=k;
mid.pop_back();
}
}
}
vector<pair<int,int>> k_mx;
for(int q=0;q<Q;q++){
k_mx.push_back(make_pair(lo[q],q));
}
sort(k_mx.rbegin(),k_mx.rend());
vector<ll> ans(Q,-1);
Fensum fen_cnt(3*N+1);
for(int i=0;i<M;i++){
activate(op[i].second,1,fen_cnt);
}
Fensum fen_curcnt(3*N+1);
for(int k=0;k<=M;k++){
if(k>0)
activate(op[k-1].second,1,fen_curcnt);
while(k_mx.size()>0&&k_mx.back().first==k){
int q = k_mx.back().second;
int u = s[q],v = e[q];
if(depth[u]>depth[v])
swap(u,v);
int z = lca(u,v);
ll C = get_sum(v,z,fen_cnt);
if(z!=u)//different path
C+=get_sum(u,z,fen_cnt);
ll curC = get_sum(v,z,fen_curcnt);
if(z!=u)//different path
curC+=get_sum(u,z,fen_curcnt);
if(gold[q]-(C-curC)>=0)
ans[q]=gold[q]-(C-curC);
k_mx.pop_back();
}
}
for(int i=0;i<Q;i++){
cout << ans[i] << endl;
}
}
