#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define int long long
struct Node
{
int start;
int stop;
int cost;
int ind;
Node(int start, int stop, int cost, int ind) : start(start),
stop(stop), cost(cost), ind(ind) {};
Node() = default;
};
struct Query
{
int l, r;
int ser;
int gold;
int ind;
Query(int l, int r, int ser, int gold, int ind) : l(l), r(r), ser(ser), gold(gold), ind(ind) {};
Query() = default;
};
std::vector<int>
tin;
std::vector<int> order;
int T = 0;
void dfs(int v, std::vector<std::vector<Node>> &g, int pred = -1)
{
for (auto u : g[v])
{
if (u.stop != pred)
{
tin[u.stop] = order.size();
order.push_back(u.ind);
dfs(u.stop, g, v);
order.push_back(u.ind);
}
}
}
const int LEN = 1;
struct Corn
{
int n;
std::vector<int> a;
std::vector<int> sum;
std::vector<int> cnt;
int all;
Corn(int n) : n(n)
{
all = 0;
a.resize(n);
cnt.resize((n + LEN - 1) / LEN + 2);
sum.resize(cnt.size());
}
void add(int i, int x)
{
// std::cout << "add " << i << ' ' << x << std::endl;
all++;
assert(a[i] == 0);
a[i] += x;
sum[i / LEN] += x;
cnt[i / LEN]++;
}
void del(int i)
{
// std::cout << "del " << a[i] << std::endl;
assert(a[i] != 0);
all--;
sum[i / LEN] -= a[i];
cnt[i / LEN]--;
a[i] = 0;
}
int need_gold(int ser)
{
// for (int i = 0; i < a.size(); i++)
// {
// std::cout << a[i] << ' ';
// }
// std::cout << std::endl;
int cnt1 = 0;
int ind = -1;
for (int i = 0; i < sum.size(); i++)
{
if (ser < sum[i])
{
ind = i;
break;
}
else
{
ser -= sum[i];
cnt1 += cnt[i];
}
}
if (ind == -1)
{
return 0;
}
for (int j = LEN * ind; j < std::min((int)a.size(),
(LEN) * (ind + 1));
j++)
{
if (a[j] != 0)
{
if (ser >= a[j])
{
ser -= a[j];
cnt1++;
}
else
{
return all - cnt1;
}
}
}
assert(0);
}
};
signed
main()
{
int n, m, q;
std::cin >> n >> m >> q;
tin.resize(n);
std::vector<Node> all;
std::vector<std::vector<Node>> g(n);
for (int i = 0; i < n - 1; i++)
{
int a, b;
std::cin >> a >> b;
a--, b--;
g[a].push_back(Node(a, b, 0, i));
g[b].push_back(Node(b, a, 0, i));
}
std::vector<std::pair<int, int>> tmp(m);
for (int i = 0; i < m; i++)
{
std::cin >> tmp[i].first >> tmp[i].second;
tmp[i].first--;
}
std::sort(tmp.begin(), tmp.end(), [&](std::pair<int, int> a, std::pair<int, int> b)
{ return a.second < b.second; });
std::vector<std::vector<int>> need(n - 1);
for (int i = 0; i < m; i++)
{
need[tmp[i].first].push_back(i);
}
tin[0] = -1;
dfs(0, g);
// for (int i : order)
// {
// std::cout << i << ' ';
// }
// std::cout << std::endl;
std::vector<Query> qu(q);
for (int i = 0; i < q; i++)
{
int start, stop, x, y;
std::cin >> start >> stop >> x >> y;
start--, stop--;
if (tin[start] > tin[stop])
{
std::swap(start, stop);
}
if (start == stop)
{
assert(0);
}
// std::cout << tin[start] << ' ' << tin[stop] << std::endl;
qu[i] = Query(tin[start] + 1, tin[stop], y, x, i);
}
std::sort(qu.begin(), qu.end(), [&](Query a, Query b)
{
if (a.l / LEN != b.l / LEN){
return a.l < b.l;
}
return a.r < b.r; });
Corn t(m);
int l = -1, r = -1;
std::vector<int> count(n - 1);
std::vector<int> ans(q);
for (int i = 0; i < q; i++)
{
while (l > qu[i].l)
{
l--;
count[order[l]] += 1;
count[order[l]] %= 2;
if (count[order[l]] == 0)
{
for (int j : need[order[l]])
{
t.del(j);
}
}
else
{
for (int j : need[order[l]])
{
t.add(j, tmp[j].second);
}
}
}
while (r < qu[i].r)
{
r++;
count[order[r]]++;
count[order[r]] %= 2;
if (count[order[r]] == 0)
{
for (int j : need[order[r]])
{
t.del(j);
}
}
else
{
for (int j : need[order[r]])
{
t.add(j, tmp[j].second);
}
}
}
while (l < qu[i].l)
{
if (l == -1)
{
l++;
continue;
}
// std::cout << l << ' ' << order[l] << "djsf; " << ' ' << count[order[l]] << std::endl;
count[order[l]]--;
count[order[l]] += 2;
count[order[l]] %= 2;
if (count[order[l]] == 0)
{
for (int j : need[order[l]])
{
t.del(j);
}
}
else
{
for (int j : need[order[l]])
{
t.add(j, tmp[j].second);
}
}
l++;
}
while (r > qu[i].r)
{
count[order[r]]--;
count[order[r]] += 2;
count[order[r]] %= 2;
if (count[order[r]] == 0)
{
for (int j : need[order[r]])
{
t.del(j);
}
}
else
{
for (int j : need[order[r]])
{
t.add(j, tmp[j].second);
}
}
r--;
}
int need = t.need_gold(qu[i].ser);
if (need > qu[i].gold)
{
ans[qu[i].ind] = -1;
}
else
{
ans[qu[i].ind] = qu[i].gold - need;
}
}
for (int i = 0; i < q; i++)
{
std::cout << ans[i] << std::endl;
}
}
