#include<bits/stdc++.h>
#define fori(i,a,b) for(int i=a;i<=b;i++)
#define int long long
#define pb push_back
using namespace std;
typedef pair<int,int> ii;
typedef tuple<int,int,int> tp;
const int M=1e5+10;
const int N=1e3+10;
const int mod=1e9+7;
int n,m,q;
int uu[M],vv[M];
vector<int> ke[M];
// dfs
int num[M],tail[M],up[M][20],cnt=0;
void dfs(int u,int p)
{
num[u]=++cnt;
fori(i,1,17) up[u][i]=up[up[u][i-1]][i-1];
for(int v:ke[u]) {
if(v==p) continue;
up[v][0]=u;
dfs(v,u);
}
tail[u]=cnt;
}
bool anc(int u,int v)
{
return num[u]<=num[v]&&tail[u]>=tail[v];
}
int lca(int u,int v)
{
if(anc(u,v)) return u;
if(anc(v,u)) return v;
for(int i=17;i>=0;i--) if(!anc(up[u][i],v)) u=up[u][i];
return up[u][0];
}
// bit
int bit[M];
void upd(int idx,int val)
{
if(idx==0) return ;
while(idx<=n) {
bit[idx]+=val;
idx+=idx&(-idx);
}
}
int get(int idx)
{
int res=0;
while(idx>0) {
res+=bit[idx];
idx-=idx&(-idx);
}
return res;
}
int query(int u,int v)
{
int x=lca(u,v);
return get(num[u])+get(num[v])-2*get(num[x]);
}
// solve
int ed[M],st[M],xx[M],yy[M];
int l[M],r[M],ret[M];
vector<int> Q[M];
ii edge[M];
void solve()
{
fori(i,1,q) l[i]=1,r[i]=m;
bool process=1;
while(process) {
process=0;
fori(i,1,q) {
if(l[i]>r[i]) continue;
Q[(l[i]+r[i])/2].pb(i);
process=1;
}
if(!process) break;
fori(i,1,m) {
int v=edge[i].second;
int w=edge[i].first;
upd(num[v],w);
upd(tail[v]+1,-w);
for(int idx : Q[i]) {
// cout << i << " " << st[idx] << " " << ed[idx] << " " << query(st[idx],ed[idx]) << "\n";
if(query(st[idx],ed[idx])<=yy[idx]) {
ret[idx]=i;
l[idx]=i+1;
}
else r[idx]=i-1;
}
}
fori(i,1,m) Q[i].clear();
fori(i,1,n) bit[i]=0;
}
}
void solve2()
{
fori(i,1,q) l[i]=r[i]=0;
fori(i,1,q) Q[ret[i]].pb(i);
fori(i,1,m) {
int v=edge[i].second;
upd(num[v],1);
upd(tail[v]+1,-1);
//cout << v << " ";
for(int idx : Q[i]) {
l[idx]=query(st[idx],ed[idx]);
}
}
fori(i,1,q) {
r[i]=query(st[i],ed[i]);
//cout << l[i] << " " << r[i] << "\n";
if(r[i]-l[i]<=xx[i]) cout << xx[i]-(r[i]-l[i]) << "\n";
else cout << -1 << "\n";
}
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
if(fopen("1.inp","r"))
{
freopen("1.inp","r",stdin);
freopen("1.out","w",stdout);
}
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
cin >> n >> m >> q;
fori(i,1,n-1) {
cin >> uu[i] >> vv[i] ;
ke[uu[i]].pb(vv[i]);
ke[vv[i]].pb(uu[i]);
}
up[1][0]=1;
dfs(1,0);
fori(i,1,m) {
int p,c;
cin >> p >> c;
if(up[uu[p]][0]==vv[p]) edge[i]={c,uu[p]};
else edge[i]={c,vv[p]};
}
sort(edge+1,edge+m+1);
fori(i,1,q) {
cin >> st[i] >> ed[i] >> xx[i] >> yy[i];
}
solve();
solve2();
}
