#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<long long,int>pii;
typedef pair<pii,pii>pi2;
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
vector<int>adj[100005];
int in[100005];
int out[100005];
int d[100005];
int two[25][100005];
int ptr=0;
int h[100005];
void dfs(int index, int par){
in[index]=++ptr;
for(int x=0;x<20;x++){
two[x+1][index]=two[x][two[x][index]];
}
for(auto it:adj[index]){
if(it==par) continue;
two[0][it]=index;
d[it]=d[index]+1;
//h[it]+=h[index];
dfs(it,index);
}
out[index]=++ptr;
}
void dfs2(int index, int par){
for(auto it:adj[index]){
if(it==par) continue;
h[it]+=h[index];
dfs2(it,index);
}
}
int lca(int a, int b){
if(d[a]>d[b]) swap(a,b);
int diff=d[b]-d[a];
for(int x=0;x<19;x++){
if(diff&(1<<x)){
b=two[x][b];
}
}
if(a==b) return a;
for(int x=19;x>=0;x--){
if(two[x][a]!=two[x][b]){
a=two[x][a];
b=two[x][b];
}
}
return two[0][a];
}
int fw[200005];
int fw2[200005];
void upd(int x, int y, int z){
while(x<200005){
fw[x]+=y;
fw2[x]+=z;
x+=x&(-x);
}
}
pii sum(int x){
int counter=0;
int counter2=0;
while(x>0){
counter+=fw[x];
counter2+=fw2[x];
x-=x&(-x);
}
return {counter,counter2};
}
void solve(){
int n,m,q;
cin >> n >> m >> q;
int temp,temp2;
pii edge[n-1];
for(int x=0;x<n-1;x++){
cin >> temp >> temp2;
adj[temp].push_back(temp2);
adj[temp2].push_back(temp);
edge[x]={temp,temp2};
}
dfs(1,-1);
pii check[m+1]; //cost edge
for(int x=1;x<=m;x++){
cin >> check[x].second >> check[x].first;
int index;
int road=check[x].second-1;
if(d[edge[road].first] > d[edge[road].second]){
index=edge[road].first;
}
else index=edge[road].second;
h[index]++;
//show(index,index);
}
dfs2(1,-1);
//for(int x=1;x<=n;x++){
//show2(x,x,h[x],h[x]);
//}
sort(check+1,check+m+1);
vector<array<int,5>>storage[m+1];
vector<array<int,5>>storage2[m+1];
int l[q];
int r[q];
int ans[q];
for(int x=0;x<q;x++){
int from,to,a,b;
cin >> from >> to >> a >> b;
array<int,5>take;
take={from,to,a,b,x};
storage[m/2].push_back(take);
l[x]=0;
r[x]=m;
ans[x]=-1;
}
for(int k=0;k<21;k++){
memset(fw,0,sizeof(fw));
memset(fw2,0,sizeof(fw2));
for(int x=0;x<=m;x++){
if(x>0){
int road=check[x].second-1;
int index;
if(d[edge[road].first] > d[edge[road].second]){
index=edge[road].first;
}
else index=edge[road].second;
upd(in[index],check[x].first,1);
upd(out[index],-check[x].first,-1);
}
for(auto it:storage[x]){
int from=it[0];
int to=it[1];
int a=it[2];
int b=it[3];
int id=it[4];
int ant=lca(from,to);
pii aa=sum(in[from]);
pii bb=sum(in[to]);
pii cc=sum(in[ant]);
int val=aa.first + bb.first - 2*cc.first;
if(val<=b){
l[id]=x+1;
int val2 = aa.second + bb.second - 2*cc.second;
int len=h[from]+h[to]-h[ant]*2-val2;
if(a-len>=0){
ans[id]=max(ans[id],a-len);
}
}
else{
r[id]=x-1;
}
if(l[id]<=r[id]){
storage2[(l[id]+r[id])/2].push_back(it);
}
}
}
for(int x=0;x<=m;x++){
storage[x].clear();
while(!storage2[x].empty()){
storage[x].push_back(storage2[x].back());
storage2[x].pop_back();
}
}
}
for(int x=0;x<q;x++) cout << ans[x] << "\n";
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t=1;
//freopen("in.txt","w",stdout);
//cin >> t;
while(t--){
solve();
}
}
