#pragma GCC optimize("unroll-loops")
#pragma gcc optimize("Ofast")
#pragma GCC optimization("Ofast")
#pragma optimize(Ofast)
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define str string
#define fastio ios::sync_with_stdio(0), cin.tie(0);
#define fs first
#define ss second
#define endl '\n'
#define all(x) (x).begin(), (x).end()
#define len(x) x.size()
#define print(a) \
for (auto &x : a) \
cout << x << " "; \
cout << endl;
#define printmp(a) \
for (auto &x : a) \
cout << x.fs << " " << x.ss << endl;
const int mod = 998244353;
vector<vector<pair<int, int>>> tree;
vector<int> degree, c;
vector<pair<int, int>> p;
vector<vector<int>> k;
bitset<2001> used;
void dfs(int n){
used[n] = 1;
for(auto &x : tree[n]){
if(!used[x.fs]){
p[x.fs] = {n, x.ss};
degree[x.fs] = degree[n] + 1;
dfs(x.fs);
}
}
}
void dfs(int s, int t){
if(s == t)
return;
if(degree[s] >= degree[t]){
for(auto x : k[p[s].ss])
c.push_back(x);
dfs(p[s].fs, t);
}
else{
for(auto x : k[p[t].ss])
c.push_back(x);
dfs(s, p[t].fs);
}
}
struct Lowest_Common_Ancestor
{
vector<vector<int>> LCA, Count;
vector<int> Degree;
int ans = 0;
void dfs(int u, int p, int y)
{
LCA[u][0] = p;
if(k[y].size() > 0)
Count[u][0] = k[y].size() * k[y][0];
for (auto &x : tree[u])
{
if (x.fs != p)
{
Degree[x.fs] = Degree[u] + 1;
dfs(x.fs, u, x.ss);
}
}
}
Lowest_Common_Ancestor()
{
LCA.resize(tree.size(), vector<int>((int)(log2(tree.size())) + 1));
Count.resize(tree.size(), vector<int>((int)(log2(tree.size())) + 1));
Degree.resize(tree.size(), 1);
dfs(1, -1, 0);
for (int j = 1; j < LCA[0].size(); j++)
for (int i = 1; i <= tree.size() - 1; i++)
if (LCA[i][j - 1] == -1)
LCA[i][j] = -1, Count[i][j] = Count[i][j - 1];
else
LCA[i][j] = LCA[LCA[i][j - 1]][j - 1], Count[i][j] = Count[i][j - 1] + Count[LCA[i][j - 1]][j - 1];
}
void binary_shifting(int &X, int k)
{
for (int i = LCA[X].size(); i >= 0; i--)
{
if (k >= (1 << i))
{
ans += Count[X][i];
X = LCA[X][i];
k -= (1 << i);
}
}
}
int lca(int X, int Y)
{
ans = 0;
if (Degree[X] < Degree[Y])
swap(X, Y);
if (Degree[X] != Degree[Y])
binary_shifting(X, Degree[X] - Degree[Y]);
int k = LCA[0].size() - 1;
while (X != Y)
{
int l = 0, r = k;
while (l < r)
{
int m = (l + r + 1) >> 1;
if (LCA[X][m] == LCA[Y][m])
r = m - 1;
else
l = m;
}
ans += Count[X][l] + Count[Y][l];
X = LCA[X][l];
Y = LCA[Y][l];
k = l;
}
return ans;
}
};
void solve(){
int n, m, q;
cin >> n >> m >> q;
tree.resize(n + 1);
for(int i = 0; i < n - 1; i ++){
int u, v;
cin >> u >> v;
tree[u].push_back({v, i + 1});
tree[v].push_back({u, i + 1});
}
k.resize(n);
int w;
for(int i = 0; i < m; i ++){
int u, v;
cin >> u >> v;
k[u].push_back(v);
w = v;
}
if(n <= 2000 and m <= 2000 and q <= 2000){
degree.resize(n + 1);
p.resize(n + 1);
dfs(1);
while(q --){
int s, t, x, y;
cin >> s >> t >> x >> y;
dfs(s, t);
sort(all(c));
for(int j = 0; j < c.size(); j ++){
if(c[j] <= y)
y -= c[j];
else{
x -= c.size() - j;
break;
}
}
if(x >= 0)
cout << x;
else
cout << -1;
cout << endl;
c.clear();
}
}
else{
Lowest_Common_Ancestor l;
while(q --){
int s, t, x, y;
cin >> s >> t >> x >> y;
int p = y / w, q = l.lca(s, t) / w;
q -= min(q, p);
x -= q;
if(x >= 0)
cout << x << endl;
else
cout << -1 << endl;
}
}
}
signed main()
{
fastio int t = 1;
// cin >> t;
while (t--)
{
solve();
cout << endl;
}
}
//
