#include <bits/stdc++.h>
using namespace std;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii ;
typedef pair<ll, ll> pll ;
typedef vector<pii> vii ;
typedef vector<int> veci ;
typedef vector<pll> vll ;
typedef vector<ll> vecll;
// find_by_order order_of_key
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define Mp make_pair
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " = " << x << endl
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("in.txt" , "r" , stdin) ; freopen("out.txt" , "w" , stdout);
#define lb lower_bound
#define ub upper_bound
#define for1(n) for(int i=1;i<=n;i++)
#define for0(n) for(int i=0;i<n;i++)
#define forn(n) for(int i=n;i>0;i--)
#define pq priority_queue <pii, vector<pii>, greater<pii>>
const ll inf = 2e18+7 ;// 998244353 ;// 1e9+9;
const int N=1e5+10,L=18;
int n,m,k,q,pre[N],st[N],en[N],t,pos[N],ans[N],par[N][L],h[N],fenn[N];
vector<pii>g[N];
vector<int>vec[N];
vector<ll>vecc;
pair<pair<pii,int>,pair<int,ll>>A[N];
vector<pair<pii,int>>Q[N],QQ[N];
ll fen[N];
void DFS(int v){
for(int j=1;j<L;j++)par[v][j]=par[par[v][j-1]][j-1];
st[v]=++t;
for(pii pp:g[v])if(pp.F!=par[v][0]){
int u=pp.F,i=pp.S;
h[u]=h[v]+1;
par[u][0]=v;
pos[i]=u;
DFS(u);
}
en[v]=t;
}
int LCA(int v1,int v2){
if(h[v1]<h[v2])swap(v1,v2);
int x=h[v1]-h[v2];
for(int j=0;j<L;j++)if(x>>j&1)v1=par[v1][j];
if(v1==v2)return v1;
for(int j=L-1;j>=0;j--)if(par[v1][j]!=par[v2][j]){
v1=par[v1][j];
v2=par[v2][j];
}
return par[v1][0];
}
void upd(int i,int x){
for(;i<=n;i+=i&-i)fen[i]+=x;
}
ll get(int i){
ll ans=0;
for(;i>0;i-=i&-i)ans+=fen[i];
return ans;
}
void updd(int i,int x){
for(;i<=n;i+=i&-i)fenn[i]+=x;
}
int gett(int i){
int ans=0;
for(;i>0;i-=i&-i)ans+=fenn[i];
return ans;
}
bool check(int j){
int s=A[j].F.F.F,t=A[j].F.F.S,v=A[j].F.S,g=A[j].S.F;ll c=A[j].S.S;
ll val=get(s)+get(t)-get(v)*2;
return (val<=c);
}
void get_res(int j,int x){
int s=A[j].F.F.F,t=A[j].F.F.S,v=A[j].F.S,g=A[j].S.F;ll c=A[j].S.S;
ll val=get(s)+get(t)-get(v)*2;val=c-val;val/=x;
int tt=gett(s)+gett(t)-gett(v)*2+val;
ans[j]=g+tt;
}
int main(){
fast_io
cin>>n>>m>>q;
for1(n-1){
int u,v;cin>>u>>v;
g[u].pb({v,i});
g[v].pb({u,i});
}
DFS(1);
vector<pii>vec2;
for1(m){
int j,c;cin>>j>>c;j=pos[j];
pre[st[j]]++;pre[en[j]+1]--;
vecc.pb(c);
vec2.pb({j,c});
}
for1(n)pre[i]+=pre[i-1];
vecc.pb(-1);
sort(all(vecc));vecc.resize(unique(all(vecc))-vecc.begin());
for(pii p:vec2){
p.S=lb(all(vecc),p.S)-vecc.begin();
vec[p.S].pb(p.F);
}
for1(q){
int s,t,g;ll c;cin>>s>>t>>g>>c;
int v=LCA(s,t);
s=st[s];t=st[t];v=st[v];
g=g-pre[s]-pre[t]+pre[v]*2;
A[i]={{{s,t},v},{g,c}};
Q[vecc.size()/2].pb({{0,vecc.size()},i});
}
for(int _=0;_<L;_++){
for(int i=0;i<vecc.size();i++){
for(int v:vec[i]){
upd(st[v],vecc[i]);
upd(en[v]+1,-vecc[i]);
}
for(pair<pii,int>p:Q[i]){
int l=p.F.F,r=p.F.S,j=p.S;
if(check(j))l=i;
else r=i;
int mid=(l+r)>>1;
QQ[mid].pb({{l,r},j});
}
}
memset(fen,0,sizeof(fen));
for0(vecc.size()){
swap(QQ[i],Q[i]);
QQ[i].clear();
}
}
vecc.pb(inf);
for(int i=0;i<vecc.size()-1;i++){
for(int v:vec[i]){
upd(st[v],vecc[i]);
upd(en[v]+1,-vecc[i]);
updd(st[v],1);
updd(en[v]+1,-1);
}
for(pair<pii,int>p:Q[i])
get_res(p.S,vecc[i+1]);
}
for1(q)cout<<max(ans[i],-1)<<endl;
}
