#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define sz size()
#define vll vector<ll>
#define bc back()
#define ar array
using namespace std;
template <class _T>
bool chmin(_T &x, const _T &y){
if (x>y)x=y;
return x>y;
}
template <class _T>
bool chmax(_T &x, const _T &y){
if (x<y)x=y;
return x<y;
}
//void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
const ll inf=1e18+7;
const ll mod=1e9+7;
const ll N=3e5+5;
const ld eps=1e-9;
struct fen{
ll n;
vll f;
fen(ll m){
n=m;
f.resize(n+1,0);
}
void upd(ll a,ll x){
for(ll i=a;i<=n;i+=i&-i){
f[i]+=x;
}
}
ll pref(ll a){
ll res=0;
for(ll i=a;i>0;i-=i&-i)
res+=f[i];
return res;
}
};
vector<vll> g(N);
ll p[N][20],sum[N][20];
ll tin[N],tout[N],d[N];
ll tiktak;
void dfs(ll v){
tin[v]=++tiktak;
for(auto i : g[v]){
if(i==p[v][0]) continue;
p[i][0]=v;
d[i]=d[v]+1;
dfs(i);
}
tout[v]=tiktak;
}
ll lca(ll a,ll b){
if(d[a]<d[b]) swap(a,b);
for(ll i=19;i>=0;i--){
if(d[a]-d[b]>=(1ll<<i)) a=p[a][i];
}
if(a==b) return a;
for(ll i=19;i>=0;i--){
if(p[a][i]!=p[b][i]){
a=p[a][i];
b=p[b][i];
}
}
return p[a][0];
}
ll get(ll a,ll d){
ll res=0;
for(ll i=0;i<20;i++){
if(d&(1ll<<i)){
res+=sum[a][i];
a=p[a][i];
}
}
return res;
}
void solve(){
ll i,j;
ll a=1,b;
ll n,m,q;
cin>>n>>m>>q;
vector<ar<ll,2>> edge;
for(i=1;i<n;i++){
cin>>a>>b;
g[a].pb(b);
g[b].pb(a);
edge.pb({a,b});
}
dfs(1);
vector<ar<ll,2>> add;
for(i=0;i<m;i++){
ll p,c; cin>>p>>c;
auto [a,b]=edge[p-1];
if(d[a]<d[b]) swap(a,b);
add.pb({a,c});
sum[a][0]++;
}
sort(all(add),[&](auto a,auto b){
return a[1]<b[1];
});
for(j=1;j<20;j++){
for(i=1;i<=n;i++){
p[i][j]=p[p[i][j-1]][j-1];
sum[i][j]=sum[i][j-1]+sum[p[i][j-1]][j-1];
}
}
vector<ar<ll,4>> qs(q);
vll path,lc;
vector<ar<ll,2>> rng(q,{0,m+1});
for(auto &a : qs){
for(i=0;i<4;i++) cin>>a[i];
lc.pb(lca(a[0],a[1]));
ll ch=get(a[0],d[a[0]]-d[lc.bc])+get(a[1],d[a[1]]-d[lc.bc]);
path.pb(ch);
}
vll ans(q);
for(i=0;i<q;i++){
ans[i]=qs[i][2]-path[i];
}
while(true){
bool flag=true;
fen f1(n+2),f2(n+2);
vector<vll> mid(m+5);
for(i=0;i<q;i++){
if(rng[i][1]-rng[i][0]>1){
ll m=(rng[i][0]+rng[i][1])/2;
mid[m].pb(i);
flag=false;
}
}
if(flag) break;
for(i=0;i<=m;i++){
for(auto it : mid[i]){
auto [s,t,g,sil]=qs[it];
ll Lc=lc[it],ch=path[it];
ll sum=f1.pref(tin[s])+f1.pref(tin[t])-2*f1.pref(tin[Lc]);
ll cnt=f2.pref(tin[s])+f2.pref(tin[t])-2*f2.pref(tin[Lc]);
ch-=cnt;
if(sum<=sil){
chmax(ans[it],g-ch);
rng[it][0]=i;
}else rng[it][1]=i;
}
if(i<m){
auto [a,c]=add[i];
f1.upd(tin[a],c);
f1.upd(tout[a]+1,-c);
f2.upd(tin[a],1);
f2.upd(tout[a]+1,-1);
}
}
}
for(i=0;i<q;i++)cout<<(ans[i]<0 ? -1 : ans[i])<<endl;
}
signed main(){
start();
ll t=1;
//cin>>t;
while(t--) solve();
return 0;
}
