using namespace std;
#include<bits/stdc++.h>
const int MXN = 1e5 + 5;
const int MXM = 1e5 + 5;
#define int long long
struct Node {
using ptr = shared_ptr<Node>;
ptr left, right;
int sum = 0;
int cnt = 0;
Node() = default;
Node(int sum, int cnt, ptr left = nullptr, ptr right = nullptr)
: sum(sum), cnt(cnt), left(left), right(right) {}
ptr get_left() {
if (!left) left = make_shared<Node>();
return left;
}
ptr get_right() {
if (!right) right = make_shared<Node>();
return right;
}
ptr update(int l, int r, int add, int tl = 0, int tr = MXN) {
if (tl >= r || tr <= l) return make_shared<Node>(sum, cnt, left, right);
if (tl >= l && tr <= r) return make_shared<Node>(sum + add, cnt + 1, left, right);
int tm = (tl + tr) / 2;
return make_shared<Node>(
sum, cnt,
get_left()->update(l, r, add, tl, tm),
get_right()->update(l, r, add, tm, tr)
);
}
pair<int, int> query(int i, int tl = 0, int tr = MXN) const {
if (tl + 1 == tr) return {sum, cnt};
int tm = (tl + tr) / 2;
if (i < tm) {
if (!left) return {sum, cnt};
auto res = left->query(i, tl, tm);
return {res.first + sum, res.second + cnt};
} else {
if (!right) return {sum, cnt};
auto res = right->query(i, tm, tr);
return {res.first + sum, res.second + cnt};
}
}
};
Node::ptr pers_st[MXM];
int in[MXN], out[MXN], depth[MXN], jmp[MXN][20];
vector<int> tree[MXN];
int t = 0;
void dfs1(int u, int p = -1) {
jmp[u][0] = p;
for (int i = 1; i < 20; i++) {
if (jmp[u][i - 1] == -1) {
jmp[u][i] = -1;
continue;
}
jmp[u][i] = jmp[jmp[u][i - 1]][i - 1];
}
in[u] = t++;
for (int v : tree[u]) {
if (v == p) continue;
depth[v] = depth[u] + 1;
dfs1(v, u);
}
out[u] = t;
}
int lca(int u, int v) {
if (depth[u] < depth[v]) swap(u, v);
for (int i = 0; i < 20; i++) {
if ((depth[u] - depth[v]) & (1 << i)) {
u = jmp[u][i];
}
}
if (u == v) return u;
for (int i = 19; i >= 0; i--) {
if (jmp[u][i] != jmp[v][i]) {
u = jmp[u][i];
v = jmp[v][i];
}
}
return jmp[u][0];
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int N, M, Q;
cin >> N >> M >> Q;
vector<pair<int, int>> edges(N - 1);
for (int i = 0; i < N - 1; i++) {
int u, v;
cin >> u >> v;
u--; v--;
tree[u].push_back(v);
tree[v].push_back(u);
edges[i] = {u, v};
}
dfs1(0);
vector<pair<int, int>> cs(M);
for (int i = 0; i < M; i++) {
int ei, c;
cin >> ei >> c;
ei--;
cs[i] = {c, ei};
}
sort(cs.begin(), cs.end());
pers_st[0] = make_shared<Node>();
for (int i = 1; i <= M; i++) {
auto [c, ei] = cs[i - 1];
auto [u, v] = edges[ei];
if (depth[u] < depth[v]) swap(u, v);
pers_st[i] = pers_st[i - 1]->update(in[u], out[u], c);
}
for (int i = 0; i < Q; i++) {
int u, v, g, s;
cin >> u >> v >> g >> s;
u--; v--;
int w = lca(u, v);
auto eval = [&](int k) {
auto [a1, a2] = pers_st[k]->query(in[u]);
auto [b1, b2] = pers_st[k]->query(in[v]);
auto [c1, c2] = pers_st[k]->query(in[w]);
return pair<int, int>{a1 + b1 - 2 * c1, a2 + b2 - 2 * c2};
};
int l = 0;
int r = M + 1;
while (l + 1 < r) {
int m = (l + r) / 2;
auto res = eval(m);
if (res.first > s) {
r = m;
} else {
l = m;
}
}
int cnt = eval(l).second;
int tot_cnt = eval(M).second;
if (tot_cnt - cnt > g) {
cout << -1 << '\n';
} else {
cout << g - (tot_cnt - cnt) << '\n';
}
}
return 0;
}
