#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define pll pair <ll,ll>
#define fi first
#define se second
#define sz(a) (ll((a).size()))
#define MASK(i) (1LL<<(i))
#define BIT(mask,i) (((mask) >> (i))&1LL)
const ll MAXN = 1e5;
const ll MAXK = 17;
vector <ll> g[MAXN + 100];
ll in[MAXN+100],out[MAXN+100];
ll timeDFS;
ll sp[MAXN+100][MAXK];
ll depth[MAXN+100];
pll edge[MAXN+100];
pll station[MAXN + 100];
ll pl[MAXN+100],pr[MAXN+100],pans[MAXN+100],ans[MAXN+100];
struct query{
ll s,t,x,y,l;
};
query all[MAXN + 100];
ll n,m,q;
namespace seg{
pll operator + (pll x,pll y){
return {x.fi+y.fi,x.se+y.se};
}
pll operator - (pll x,pll y){
return {x.fi-y.fi,x.se-y.se};
}
pll tree[MAXN*4+100];
void init(){
for (ll i = 1;i <= n*4+10;i++)tree[i] = {0,0};
}
void add(ll id,pll delta){
tree[id] = tree[id]+delta;
}
void lz(ll id){
add(id<<1,tree[id]);
add(id<<1|1,tree[id]);
tree[id] = {0,0};
}
void update(ll id,ll l,ll r,ll l1,ll r1,pll delta){
if (l > r1 || l1 > r)return;
if (l1 <= l && r <= r1){
add(id,delta);
return;
}
lz(id);
ll mid = (l + r) >> 1;
update(id<<1,l,mid,l1,r1,delta);
update(id<<1|1,mid+1,r,l1,r1,delta);
}
pll get(ll id,ll l,ll r,ll i){
if (l == r){
return tree[id];
}
lz(id);
ll mid = (l + r) >> 1;
if (mid >= i)return get(id<<1,l,mid,i);
else return get(id<<1|1,mid+1,r,i);
}
void update(ll u,ll silver){
update(1,1,n,in[u],out[u],{-1,silver});
}
pll get(ll i){
return get(1,1,n,in[i]);
}
void gold(ll u){
update(1,1,n,in[u],out[u],{+1,0});
}
pll eval(query x){
return get(x.s)+get(x.t)-get(x.l)-get(x.l);
}
}
ll lca(ll u,ll v){
if (depth[u] > depth[v])swap(v,u);
for (ll j = MAXK-1;j >= 0;j --){
if (depth[v] - MASK(j) >= depth[u]){
v = sp[v][j];
}
}
if (u==v)return u;
for (ll j = MAXK-1;j >= 0;j --){
if (sp[u][j] != sp[v][j]){
u = sp[u][j];
v = sp[v][j];
}
}
return sp[u][0];
}
void dfs(ll u,ll p){
in[u] = ++timeDFS;
depth[u] = depth[p]+1;
sp[u][0] = p;
for (ll i = 1;i < MAXK;i ++){
sp[u][i] = sp[sp[u][i-1]][i-1];
}
for (auto v:g[u]){
if (v==p)continue;
dfs(v,u);
}
out[u] = timeDFS;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
cin>>n>>m>>q;
for (ll i = 1;i < n;i ++){
ll u,v;
cin>>u>>v;
edge[i] = {u,v};
g[u].push_back(v);
g[v].push_back(u);
}
dfs(1,1);
for (ll i = 1;i <= m;i ++){
cin>>station[i].se>>station[i].fi;
ll u = edge[station[i].se].fi, v = edge[station[i].se].se;
if (depth[u] < depth[v])station[i].se = v;
else station[i].se = u;
// cout<<station[i].fi<<' '<<station[i].se<<'\n';
}
sort(station+1,station+1+m);
for (ll i = 1;i <= q;i ++){
cin>>all[i].s>>all[i].t>>all[i].x>>all[i].y;
all[i].l = lca(all[i].s,all[i].t);
}
for (ll i = 1;i <= q;i ++){
pl[i] = 0;
pr[i] = m;
pans[i] = -1;
}
while (1){
vector <pll> ask;
for (ll i = 1;i <= q;i ++){
if (pl[i] <= pr[i]){
ask.emplace_back((pl[i]+pr[i])/2,i);
}
}
if (ask.empty())break;
sort(ask.begin(),ask.end());
ll ptr = 0;
seg::init();
for (ll i = 1;i <= m;i ++){
seg::gold(station[i].se);
}
for (ll i = 0;i <= m;i ++){
if (i)seg::update(station[i].se,station[i].fi);
while (ptr<sz(ask) && ask[ptr].fi == i){
ll id = ask[ptr].se;
pll tmp = seg::eval(all[id]);
if (all[id].y >= tmp.se){
pans[id] = i;
pl[id] = i+1;
ans[id] = tmp.fi;
}
else{
pr[id] = i-1;
}
ptr++;
}
}
}
for (ll i = 1;i <= q;i ++){
// cout<<pans[i]<<' ';
if (ans[i] > all[i].x){cout<<-1;}
else cout<<all[i].x-ans[i];
cout<<'\n';
}
return 0;
}
