#include<bits/stdc++.h>
#define taskname "A"
using namespace std;
typedef long long ll;
const int lim = 1e5 + 5;
int n, m, q, u[lim], v[lim];
vector<int>g[lim], c[lim];
namespace sub1{
void solve(){
queue<int>Q;
vector<int>h(n + 1, -1), parent(n + 1);
vector<vector<int>>value(n + 1);
Q.push(parent[1] = h[1] = 1);
while(!Q.empty()){
int s = Q.front();
Q.pop();
for(int& i : g[s]){
int d = u[i] ^ v[i] ^ s;
if(h[d] == -1){
h[d] = h[parent[d] = s] + 1;
value[d] = c[i];
Q.push(d);
}
}
}
for(int _ = 0; _ < q; _++){
int s, t, x;
ll y;
cin >> s >> t >> x >> y;
vector<int>path_value;
while(s != t){
if(h[s] < h[t]){
swap(s, t);
}
for(int& x : value[s]){
path_value.emplace_back(x);
}
s = parent[s];
}
sort(path_value.begin(), path_value.end());
int p = path_value.size();
for(int i = 0; i < path_value.size(); i++){
if((y -= path_value[i]) < 0){
p = i;
break;
}
}
cout << max(-1, x - int(path_value.size()) + p) << "\n";
}
}
}
namespace sub23{
struct Node{
int lc, rc, cnt;
ll sum;
Node(){
this->lc = this->rc = -1;
this->cnt = 0;
this->sum = 0;
}
};
vector<Node>st;
void build(int id, int l, int r){
if(l == r){
return;
}
int m = (l + r) >> 1;
st.emplace_back(Node());
build(st[id].lc = int(st.size()) - 1, l, m);
st.emplace_back(Node());
build(st[id].rc = int(st.size()) - 1, m + 1, r);
}
void update(int id, int l, int r, int p, int x){
st[id].sum += x;
st[id].cnt++;
if(l == r){
return;
}
int m = (l + r) >> 1;
if(m < p){
st.emplace_back(st[st[id].rc]);
update(st[id].rc = int(st.size()) - 1, m + 1, r, p, x);
}
else{
st.emplace_back(st[st[id].lc]);
update(st[id].lc = int(st.size()) - 1, l, m, p, x);
}
}
int h[lim], _c[lim], fc[lim], up[lim][17];
void dfs(int s){
for(int& i : g[s]){
int d = u[i] ^ v[i] ^ s;
if(d != up[s][0]){
h[d] = h[up[d][0] = s] + 1;
fc[d] = fc[s] + c[i].size();
for(int i = 1; i < 17; i++){
up[d][i] = up[up[d][i - 1]][i - 1];
}
st[d] = st[s];
for(int& x : c[i]){
update(d, 1, m, lower_bound(_c + 1, _c + m + 1, x) - _c, x);
}
dfs(d);
}
}
}
int lca(int u, int v){
if(h[u] < h[v]){
swap(u, v);
}
for(int i = 0, k = h[u] - h[v]; i < 17; i++){
if(1 << i & k){
u = up[u][i];
}
}
if(u == v){
return u;
}
for(int i = 16; i > -1; i--){
if(up[u][i] != up[v][i]){
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
void solve(){
for(int i = 1, p = 0; i <= n; i++){
for(int& x : c[i]){
_c[++p] = x;
}
}
sort(_c + 1, _c + m + 1);
st.assign(n + 1, Node());
build(1, 1, m);
memset(up, fc[1] = 0, sizeof(up));
dfs(h[1] = 1);
for(int _ = 0; _ < q; _++){
int s, t, x;
ll y;
cin >> s >> t >> x >> y;
int p = lca(s, t), ids = s, idt = t, idp = p, l = 1, r = m, rem_cnt = 0;
while(l < r){
int m = (l + r) >> 1;
ll left = st[st[ids].lc].sum + st[st[idt].lc].sum - (st[st[idp].lc].sum << 1LL);
if(left <= y){
y -= left;
rem_cnt += st[st[ids].lc].cnt + st[st[idt].lc].cnt - (st[st[idp].lc].cnt << 1);
ids = st[ids].rc;
idt = st[idt].rc;
idp = st[idp].rc;
l = m + 1;
}
else{
ids = st[ids].lc;
idt = st[idt].lc;
idp = st[idp].lc;
r = m;
}
}
cout << max(-1, x - fc[s] - fc[t] + (fc[p] << 1) + rem_cnt + (int)min(ll(st[ids].cnt + st[idt].cnt - (st[idp].cnt << 1)), y / _c[l])) << "\n";
}
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if(fopen(taskname".inp", "r")){
freopen(taskname".inp", "r", stdin);
}
cin >> n >> m >> q;
for(int i = 1; i < n; i++){
cin >> u[i] >> v[i];
g[u[i]].emplace_back(i);
g[v[i]].emplace_back(i);
}
memset(c, 0, sizeof(c));
for(int i = 0; i < m; i++){
int p, x;
cin >> p >> x;
c[p].emplace_back(x);
}
if(max(max(n, m), q) <= 2000){
sub1::solve();
}
else{
sub23::solve();
}
}
