#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
ll ver[100005],tin[100005],ass=0;
bool vis[100005];
vector<pair<ll,ll> >adj[100005];
ll uu[100005],v[100005],cnt[100005];
vector<ll>roads[100005];
vector<ll>disc;
ll revdisc[100005];
ll up[100005][20];
ll dep[100005];
ll assver=1;
ll siz;
struct EZOKUSEG{
vector<vector<ll> >seg;
vector<vector<ll> >chl,chr,cntt;
void init(ll n){
seg.resize(4*n+5),chl.resize(4*n+5),chr.resize(4*n+5),cntt.resize(4*n+5);
}
void build(ll l, ll r, ll id){
seg[id].pb(0);
chl[id].pb(0),chr[id].pb(0),cntt[id].pb(0);
if(l==r){
return;
}
ll mid=(l+r)>>1;
build(l,mid,id*2);
build(mid+1,r,id*2+1);
}
void upd(ll ver, ll ul, ll l, ll r, ll val, ll id){
if(l==r){
seg[id].pb(seg[id][ver]+val);
cntt[id].pb(cntt[id][ver]+1);
return;
}
else{
ll mid=(l+r)>>1;
if(ul<=mid){
upd(chl[id][ver],ul,l,mid,val,id*2);
ll st=seg[id*2].size()-1,st2=chr[id][ver];
chl[id].pb(seg[id*2].size()-1);
chr[id].pb(chr[id][ver]);
seg[id].pb(seg[id*2][st]+seg[id*2+1][st2]);
cntt[id].pb(cntt[id*2][st]+cntt[id*2+1][st2]);
}
else{
upd(chr[id][ver],ul,mid+1,r,val,id*2+1);
ll st=chl[id][ver],st2=seg[id*2+1].size()-1;
chl[id].pb(st);
chr[id].pb(st2);
seg[id].pb(seg[id*2][st]+seg[id*2+1][st2]);
cntt[id].pb(cntt[id*2][st]+cntt[id*2+1][st2]);
}
}
}
ll sum(ll ver, ll ql, ll qr, ll l, ll r, ll id){
if(l>qr||r<ql){
return 0;
}
if(l>=ql&&r<=qr){
return seg[id][ver];
}
ll mid=(l+r)>>1;
return sum(chl[id][ver],ql,qr,l,mid,id*2)+sum(chr[id][ver],ql,qr,mid+1,r,id*2+1);
}
ll sum2(ll ver, ll ql, ll qr, ll l, ll r, ll id){
if(l>qr||r<ql){
return 0;
}
if(l>=ql&&r<=qr){
return cntt[id][ver];
}
ll mid=(l+r)>>1;
return sum2(chl[id][ver],ql,qr,l,mid,id*2)+sum2(chr[id][ver],ql,qr,mid+1,r,id*2+1);
}
}st;
void dfs(ll s, ll p, ll k){
vis[s]=1;
tin[s]=ass++;
ll curver=ver[p];
for(int i=0;i<roads[k].size();i++){
ll popo=lower_bound(disc.begin(),disc.end(),roads[k][i])-disc.begin()+1;
st.upd(curver,popo,1,siz,roads[k][i],1);
curver=assver++;
}
ver[s]=curver;
for(pair<ll,ll>& u: adj[s]){
if(!vis[u.first]){
up[u.first][0]=s;
dep[u.first]=dep[s]+1;
dfs(u.first,s,u.second);
}
}
}
ll jump(ll u, ll k){
for(int i=19;i>=0;i--){
if(k&(1<<i)){
u=up[u][i];
}
}
return u;
}
ll lca(ll u, ll v){
if(dep[u]<dep[v]){
swap(u,v);
}
u=jump(u,dep[u]-dep[v]);
if(u==v){
return u;
}
for(int i=19;i>=0;i--){
if(up[u][i]!=up[v][i]){
u=up[u][i],v=up[v][i];
}
}
return up[u][0];
}
bool ck(ll a, ll b, ll com, ll par, ll gin){
ll tot=st.sum(ver[a],1,par,1,siz,1)+st.sum(ver[b],1,par,1,siz,1)-2*st.sum(ver[com],1,par,1,siz,1);
return (gin>=tot);
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
ll n,m,q;
cin>>n>>m>>q;
for(int i=1;i<=n-1;i++){
cin>>uu[i]>>v[i];
adj[uu[i]].pb({v[i],i});
adj[v[i]].pb({uu[i],i});
}
for(int i=1;i<=m;i++){
ll p,c;
cin>>p>>c;
disc.pb(c);
roads[p].pb(c);
cnt[p]++;
}
sort(disc.begin(),disc.end());
disc.erase(unique(disc.begin(),disc.end()),disc.end());
siz=disc.size();
st.init(disc.size());
st.build(1,siz,1);
for(int i=0;i<disc.size();i++){
revdisc[i+1]=disc[i];
}
ver[0]=0;
ver[1]=0;
dfs(1,0,0);
up[1][0]=1;
for(int j=1;j<=19;j++){
for(int i=1;i<=n;i++){
up[i][j]=up[up[i][j-1]][j-1];
}
}
// for(int i=1;i<=n;i++){
// cout<<ver[i]<<" ";
// }
// cout<<st.sum(ver[4],1,siz,1,siz,1)<<'\n';
while(q--){
ll s,t,kin,gin;
cin>>s>>t>>kin>>gin;
ll com=lca(s,t);
ll l=1,r=disc.size();
while(l<r){
ll mid=(l+r)>>1;
// cout<<mid<<'\n';
if(ck(s,t,com,mid,gin)){
l=mid+1;
}
else{
r=mid;
}
}
if(ck(s,t,com,l,gin)){
cout<<kin<<'\n';
continue;
}
ll tot=st.sum(ver[s],1,l-1,1,siz,1)+st.sum(ver[t],1,l-1,1,siz,1)-2*st.sum(ver[com],1,l-1,1,siz,1);
ll used=st.sum2(ver[s],1,l-1,1,siz,1)+st.sum2(ver[t],1,l-1,1,siz,1)-2*st.sum2(ver[com],1,l-1,1,siz,1);
gin-=tot;
ll ned=revdisc[l];
gin/=ned;
used+=gin;
ll bruh=st.sum2(ver[s],1,siz,1,siz,1)+st.sum2(ver[t],1,siz,1,siz,1)-2*st.sum2(ver[com],1,siz,1,siz,1);
bruh-=used;
// cout<<bruh<<'\n';
if(kin>=bruh){
cout<<kin-bruh<<'\n';
}
else{
cout<<"-1\n";
}
}
}
