#include <bits/stdc++.h>
using namespace std;
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1};
#define endl "\n"
#define int ll
using ull=unsigned long long;
using ll=long long;
using pii=pair<int,int>;
const int mod=1e9+7;
#define OVL(x,s) for(auto y:x) cout<<y<<s; cout<<"\n";
template <typename T> istream& operator>>(istream& is, vector<T> &a) {
copy_n(istream_iterator<T>(is), a.size(), a.begin()); return is;}
#ifdef IOI
void dbg_out() { cout << endl; } template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__);
#else
#define dbg(...) 1337;
#endif
#define pb push_back
#define F first
#define S second
#define all(v) v.begin(),v.end()
const int mxn=1e5+100;
const int LOGN=20;
vector<pair<int,int>> ed;
vector<vector<int>> f;
vector<int> v[mxn];
int depth[mxn];
int pos[mxn];
int top[mxn];
int sz[mxn];
int up[mxn][LOGN+1];
map<pii,int> mp;
map<int,pii> mp2;
vector<vector<int>> queries;
void dfs(int node,int par){
depth[node]=depth[par]+1;
up[node][0]=par;
for(int i=1;i<=LOGN;i++){
up[node][i]=up[up[node][i-1]][i-1];
}
sz[node]=1;
for(auto x:v[node]){
if(x==par){continue;}
dfs(x,node);
sz[node]+=sz[x];
}
}
int LCA(int a,int b){
if(depth[a]<depth[b]) swap(a,b);
int d=depth[a]-depth[b];
for(int i=LOGN;i>=0;i--){
if(d&(1<<i)) a=up[a][i];
}
if(a==b) return a;
for(int i=LOGN;i>=0;i--){
if(up[a][i]!=up[b][i]){
a=up[a][i];
b=up[b][i];
}
}
return up[a][0];
}
int c=1;
int cID=1;
void HLD(int node,int par,int cID){
top[node]=cID;
pos[node]=c;
c++;
int bst=0;
int b=-1;
for(auto x:v[node]){
if(x==par) continue;
if(b<sz[x]){
b=sz[x];
bst=x;
}
}
if(b!=-1){
HLD(bst,node,cID);
}
for(auto x:v[node]){
if(x==par||x==bst) continue;
HLD(x,node,x);
}
}
const int MAXN=2e5+100;
int BIT[MAXN];
int BIT2[MAXN];
void add(int i,int x){
i++;
while(i<MAXN){
BIT[i]+=x;
BIT2[i]+=(x>0?1:-1);
i+=(i&(-i));
}
}
int qqqq(int i){
i++;
int ans=0;
while(i){
ans+=BIT[i];
i-=(i&-i);
}
return ans;
}
int qqqq1(int i){
i++;
int ans=0;
while(i){
ans+=BIT2[i];
i-=(i&-i);
}
return ans;
}
int query(int l,int r){
if(l>r) return 0;
return qqqq(r)-qqqq(l-1);
}
int query1(int l,int r){
if(l>r) return 0;
return qqqq1(r)-qqqq1(l-1);
}
map<pii,int> updated,upp;
pair<int,int> qq(int u,int v){
pair<int,int> ans(0,0);
while(top[u]!=top[v]){
int l=top[v];
l=pos[l];
l++;
int r=pos[v];
// dbg(pos[top[v]],r,u,v)
ans.F+=query(l,r);
ans.S+=query1(l,r);
v=top[v];
int t=up[v][0];
if(updated.count({t,v})){
ans.F+=updated[{t,v}];
ans.S+=upp[{t,v}];
}
v=up[v][0];
}
int l=pos[u];
l++;
int r=pos[v];
ans.F+=query(l,r);
ans.S+=query1(l,r);
return ans;
}
pair<int,int> qv(int u,int v){
int l=LCA(u,v);
pair<int,int> ans(0,0);
pair<int,int> a=qq(l,u);
pair<int,int> b=qq(l,v);
ans.F=a.F+b.F;
ans.S=a.S+b.S;
return ans;
}
int sum[mxn];
int nm[mxn];
int ans[mxn];
void bs(int l,int r,vector<vector<int>> &queries){
if(l>r) return;
if(queries.empty()) return;
vector<vector<int>> ok,nok;
int mid=(l+r)/2;
for(int i=l;i<=mid;i++){
int a=f[i][0];
int b=f[i][1];
int c=f[i][2];
if(up[a][0]==b) swap(a,b);
// update(1,1,mxn,pos[b],c);
add(pos[b],c);
updated[{a,b}]+=c;
upp[{a,b}]++;
}
for(auto x:queries){
int s=x[0];
int t=x[1];
pair<int,int> as=qv(s,t);
if(sum[x[4]]>=as.F){
sum[x[4]]-=as.F;
nm[x[4]]-=as.S;
ans[x[4]]=mid;
ok.pb(x);
}else{
nok.pb(x);
}
}
for(int i=l;i<=mid;i++){
int a=f[i][0];
int b=f[i][1];
int c=f[i][2];
if(up[a][0]==b) swap(a,b);
add(pos[b],-c);
updated.erase(make_pair(a,b));
upp.erase(make_pair(a,b));
}
if(l==r){
for(auto x:queries){
if(nm[x[4]]>x[2]) ans[x[4]]=-1;
else ans[x[4]]=x[2]-nm[x[4]];
}
return;
}
bs(l,mid,nok);vector<vector<int>>().swap(nok);
bs(mid+1,r,ok);vector<vector<int>>().swap(ok);
}
signed main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
int n,m,q;
cin>>n>>m>>q;
for(int i=0;i+1<n;i++){
int a,b;
cin>>a>>b;
v[a].pb(b);
v[b].pb(a);
ed.pb({a,b});
mp[{a,b}]=mp[{b,a}]=i;
mp2[i]={a,b};
}
for(int i=0;i<m;i++){
int p,c;
cin>>p>>c;
p--;
auto [a,b]=mp2[p];
f.pb({a,b,c});
}
sort(all(f),[&](const auto &a,const auto &b ){
return a[2]<b[2];
});
for(int i=0;i<q;i++){
int s,t,x,y;
cin>>s>>t>>x>>y;
queries.pb({s,t,x,y,i});
sum[i]=y;
}
dfs(1,1);
HLD(1,1,1);
for(auto x:f){
int a=x[0];
int b=x[1];
int c=x[2];
if(up[a][0]==b) swap(a,b);
updated[{a,b}]+=c;
upp[{a,b}]++;
add(pos[b],c);
// update(1,1,mxn,pos[b],c);
}
for(auto x:queries){
int s=x[0];
int t=x[1];
nm[x[4]]=qv(s,t).S;
}
for(auto x:f){
int a=x[0];
int b=x[1];
int c=x[2];
if(up[a][0]==b) swap(a,b);
updated.erase(make_pair(a,b));
upp.erase(make_pair(a,b));
// update(1,1,mxn,pos[b],-c);
add(pos[b],-c);
}
bs(0,m-1,queries);
for(auto x:queries){
cout<<ans[x[4]]<<endl;
}
}
