#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define s second
#define f first
#define pii pair <int,int>
#define left h*2,l,(l + r)/2
#define right h*2+1,(l + r)/2 + 1,r
#define int ll
using namespace std;
const int N = 1e5 + 3,inf = 1e18;
int A[N],B[N],dep[N],d[25][N];
int L[N],R[N],S[N],T[N],X[N],Y[N],C[N],ans[N],total[N];
int timer,tin[N],tout[N],t[7][4*N],val[N];
vector <int> v[N];
void dfs(int x,int par){
d[0][x] = par;
tin[x] = ++timer;
dep[x] = dep[par] + 1;
for (int to: v[x]){
if (to != par) dfs(to,x);
}
tout[x] = timer;
}
int lca(int x,int y){
if (dep[x] < dep[y]) swap(x,y);
for (int i = 20; i >= 0; i--)
if (dep[d[i][x]] >= dep[y]) x= d[i][x];
if (x==y) return x;
for (int i=20;i>=0;i--)
if (d[i][x] != d[i][y]) {
x = d[i][x];
y = d[i][y];
}
return d[0][x];
}
void upd(int id,int h,int l,int r,int L,int R,int val){
if (r < L || R < l) return;
if (L <= l && r <= R){
t[id][h] += val;
return;
}
upd(id,left,L,R,val);
upd(id,right,L,R,val);
}
int get(int id,int h,int l,int r,int idx){
if (l == r) return t[id][h];
if (idx > (l + r)/2) return t[id][h] + get(id,right,idx);
return t[id][h] + get(id,left,idx);
}
void clear(int h,int l,int r){
t[1][h] = t[2][h] = 0;
if (l == r) return;
clear(left);
clear(right);
}
signed main (){
ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
int n,m,q;
cin>>n>>m>>q;
for (int i = 1; i < n; i++){
cin >> A[i] >> B[i];
v[A[i]].pb(B[i]);
v[B[i]].pb(A[i]);
}
dfs(1,1);
for (int j = 1; j <= 20; j++)
for (int i = 1; i <= n; i++)
d[j][i] = d[j - 1][d[j - 1][i]];
vector <pii> vec;
for (int i = 1; i <= m; i++){
int x,y;
cin>>x>>y;
vec.pb({y,x});
}
sort(vec.begin(),vec.end());
for (int i= 1; i < n; i++){
if (dep[A[i]] > dep[B[i]]) swap(A[i],B[i]);
}
for (int i = 0;i < vec.size(); i++){
int x = B[vec[i].s];
upd(3,1,1,n,tin[x],tout[x],+1);
}
for (int i = 1; i <= q; i++){
cin>>S[i]>>T[i]>>X[i]>>Y[i];
L[i] = 0;
R[i] = vec.size() - 1;
C[i] = lca(S[i],T[i]);
total[i] = get(3,1,1,n,tin[S[i]]) + get(3,1,1,n,tin[T[i]]) - 2*get(3,1,1,n,tin[C[i]]);
}
for (int j = 1; j <= 30; j++){
clear(1,1,n);
vector <pii> qr;
for (int i = 1; i <= q; i++){
int mid = (L[i] + R[i])/2;
qr.pb({mid,i});
}
sort(qr.begin(),qr.end());
int l = 0;
for (int i = 0; i < qr.size(); i++){
int id = qr[i].s,mid = qr[i].f;
while (l <= mid){
int x = B[vec[l].s];
upd(1,1,1,n,tin[x],tout[x],vec[l].f);
upd(2,1,1,n,tin[x],tout[x],1);
++l;
}
int sum = get(1,1,1,n,tin[S[id]]) + get(1,1,1,n,tin[T[id]]) - 2*get(1,1,1,n,tin[C[id]]);
if (sum <= Y[id]){
int cnt = get(2,1,1,n,tin[S[id]]) + get(2,1,1,n,tin[T[id]]) - 2*get(2,1,1,n,tin[C[id]]);
ans[id] = cnt;
L[id] = mid + 1;
}else{
R[id] = mid - 1;
}
}
}
for (int i = 1; i <= q; i++){
ans[i] = total[i] - ans[i];
if (ans[i] <= X[i]) cout<<X[i] - ans[i]<<endl;
else cout<<-1<<endl;
}
}
