#include <bits/stdc++.h>
using namespace std;
#define pb(x) push_back(x)
struct node{
int s,e,m;
long long int lazy = 0;
node *l,*r;
node(int S, int E){
s = S;
e = E;
m = (s + e)/2;
lazy = 0;
if(s != e){
l = new node(s,m);
r = new node(m + 1, e);
}
}
void update(int S, int E, int k){
if(S <= s && e <= E){
lazy += k;
return;
}
if(S <= m){
l -> update(S,E,k);
}
if(m < E){
r -> update(S,E,k);
}
}
long long int query(int i){
if(s == e) return lazy;
if(i <= m) return lazy + l -> query(i);
if(m < i) return lazy + r -> query(i);
}
}*root,*ront,*poot;
struct peep{
int s;
int e;
int m;
int i;
};
int N;
int M;
int u,v;
vector<int> adjlst[100100];
int pre[100100];
int post[100100];
int cont = 0;
int parent[100100][30];
vector<pair<int,int>> edge;
int p,c;
long long int g,s;
vector<pair<int,int> > update;
vector<pair<pair<int,int>,pair<int,long long int>> > queries;
vector<peep> pbs;
int ans[100100];
int Q;
int d[100100];
void dfs(int i, int p, int de){
pre[i] = cont;
parent[i][0] = p;
d[i] = de;
cont++;
for(int j : adjlst[i]){
if(j == p) continue;
dfs(j,i,de+1);
}
post[i] = cont - 1;
}
bool comparep(const peep &a, const peep &b){
return a.m < b.m;
}
int lca(int a, int b){
if(d[a] < d[b]) swap(a,b);
for(int i = 25; i >= 0; i--){
if(parent[a][i] != -1 && d[parent[a][i]] >= d[b]){
a = parent[a][i];
}
}
if(a == b) return a;
for(int i = 25; i >= 0; i--){
if(parent[a][i] != parent[b][i]){
a = parent[a][i];
b = parent[b][i];
}
}
return parent[a][0];
}
int main(){
scanf(" %d",&N);
scanf(" %d",&M);
scanf(" %d",&Q);
edge.push_back({0,0});
for(int i = 0; i < N - 1; i++){
scanf(" %d",&u);
scanf(" %d",&v);
adjlst[u].push_back(v);
adjlst[v].push_back(u);
edge.push_back({u,v});
}
dfs(1,-1,0);
for(int i = 1; i <= N; i++){
for(int j = 1; j < 30; j++){
parent[i][j] = -1;
}
}
for(int j = 1; j <= 25; j++){
for(int i = 1; i <= N; i++){
if(parent[i][j - 1] != -1){
parent[i][j] = parent[ parent[i][j - 1] ][j-1];
}
}
}
poot = new node(0,N-1);
for(int i = 0; i < M; i++){
scanf(" %d",&p);
scanf(" %d",&c);
update.push_back({c,p});
int u = edge[p].first;
int v = edge[p].second;
if(u == parent[v][0]) u = v;
poot -> update(pre[u],post[u],1);
}
sort(update.begin(),update.end());
for(int i = 0; i < Q; i++){
scanf(" %d",&u);
scanf(" %d",&v);
scanf(" %lld",&g);
scanf(" %lld",&s);
queries.push_back({{u,v},{g,s}});
pbs.push_back({0,M-1,(M)/2, i});
}
sort(pbs.begin(),pbs.end(),comparep);
while(!pbs.empty()){
vector<peep> process = pbs;
pbs.clear();
int it = 0;
root = new node(0,N - 1);
ront = new node(0,N - 1);
for(int i = 0; i < process.size(); i++){
while(it != M && it <= process[i].m){
int u = edge[update[it].second].first;
int p = edge[update[it].second].second;
if(u == parent[p][0]) swap(u,p);
root -> update(pre[u],post[u],update[it].first);
ront -> update(pre[u],post[u],1);
it++;
}
int j = process[i].i;
int u = queries[j].first.first;
int v = queries[j].first.second;
int c = lca(u,v);
if(process[i].s == process[i].e){
ans[j] = queries[j].second.first + (ront -> query(pre[u]) + ront -> query(pre[v]) - ront -> query(pre[c]) * 2 ) -
(poot -> query(pre[u]) + poot -> query(pre[v]) - poot -> query(pre[c]) * 2 );
}
else{
if( root -> query(pre[u]) + root -> query(pre[v]) - root -> query(pre[c]) * 2 > queries[j].second.second ){
pbs.push_back({process[i].s,process[i].m - 1, (process[i].s + process[i].m)/2, process[i].i });
}
else{
pbs.push_back({process[i].m, process[i].e, (process[i].e + process[i].m + 1)/2, process[i].i });
}
}
}
if(!pbs.empty()){
sort(pbs.begin(),pbs.end(), comparep);
}
}
for(int i = 0; i < Q; i++){
if(ans[i] >= 0) printf("%d\n",ans[i]);
else printf("-1\n");
}
}
