#include <bits/stdc++.h>
using namespace std;
#define UP1(i, n) for (int i = 0; i < (n); i++)
#define UP2(i, a, b) for (int i = (a); i <= (b); i++)
#define UP3(i, a, b, c) for (int i = (a); i <= (b); i += (c))
#define DN1(i, n) for (int i = (n) - 1; i >= 0; i--)
#define DN2(i, a, b) for (int i = (a); i >= (b); i--)
#define DN3(i, a, b, c) for (int i = (a); i >= (b); i -= (c))
#define FOR_IMPL(_1, _2, _3, _4, NAME, ...) NAME
#define FOR_UP(...) FOR_IMPL(__VA_ARGS__, UP3, UP2, UP1) (__VA_ARGS__)
#define FOR_DN(...) FOR_IMPL(__VA_ARGS__, DN3, DN2, DN1) (__VA_ARGS__)
#define POPCOUNT(n) __builtin_popcountll(n)
#define CLZ(n) __builtin_clzll(n)
#define CTZ(n) __builtin_ctzll(n)
#define LOG(n) __lg(n)
#define BIT(n, i) (((n) >> (i)) & 1LL)
#define FLIP(n, i) ((n) ^ (1LL << (i)))
#define ON(n, i) ((n) | (1LL << (i)))
#define OFF(n, i) ((n) & ~(1LL << (i)))
#define all(x) (x).begin(), (x).end()
#define len(x) (int)x.size()
#define fi first
#define se second
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
#if __cplusplus <= 201402L
template <typename T> T gcd(T a, T b) {
return __gcd(a, b);
}
template <typename T> T lcm(T a, T b) {
return a / gcd(a, b) * b;
}
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rng);
}
template <class T> void remove_duplicate(vector<T> &v) {
sort(v.begin(), v.end());
v.resize(unique(v.begin(), v.end()) - v.begin());
}
template <class T> bool maximize(T &x, const T &y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T> bool minimize(T &x, const T &y) {
if (x > y) {
x = y;
return true;
}
return false;
}
const int N = 1e5 + 24, LG = 24;
int n, m, q; pii edge[N], checkpoint[N];
int tin[N], tout[N], tdfs, par[N][LG], h[N];
int L[N], R[N], ans[N]; vector<int> M[N];
array<ll, 4> query[N];
vector<int> g[N];
struct FenwickTree {
int n; ll t[N];
void init(int n_) {
n = n_; FOR_UP (i, 0, n) t[i] = 0;
}
void update(int i, ll val) {
for (; i <= n; i += i & (-i)) {
t[i] += val;
}
}
void update_range(int l, int r, ll val) {
update(l, val); update(r + 1, -val);
}
ll get(int i) {
ll res = 0; for (; i > 0; i -= i & (-i)) {
res += t[i];
}
return res;
}
} silver, gold;
void dfs(int u, int pre) {
tin[u] = ++tdfs;
par[u][0] = pre;
FOR_UP (i, 1, LG - 1) {
par[u][i] = par[par[u][i - 1]][i - 1];
}
for (int i: g[u]) {
int v = u ^ edge[i].fi ^ edge[i].se;
if (v == pre) continue;
h[v] = h[u] + 1;
dfs(v, u);
}
tout[u] = tdfs;
}
int anc(int u, int k) {
FOR_UP (i, LG) if (BIT(k, i)) u = par[u][i];
return u;
}
int lca(int u, int v) {
if (h[u] > h[v]) swap(u, v);
v = anc(v, h[v] - h[u]);
if (u == v) return u;
FOR_DN (i, LG - 1, 0) {
if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
ll silverPath(int u, int v) {
return silver.get(tin[u]) + silver.get(tin[v]) - 2 * silver.get(tin[lca(u, v)]);
}
ll goldPath(int u, int v) {
return gold.get(tin[u]) + gold.get(tin[v]) - 2 * gold.get(tin[lca(u, v)]);
}
int main() {
cin.tie(0) -> sync_with_stdio(0);
cin >> n >> m >> q;
FOR_UP (i, 1, n - 1) {
auto &[u, v] = edge[i];
cin >> u >> v;
g[u].push_back(i);
g[v].push_back(i);
}
FOR_UP (i, 1, m) {
auto &[p, c] = checkpoint[i];
cin >> p >> c;
swap(p, c);
}
FOR_UP (i, 1, q) {
auto &[s, t, x, y] = query[i];
cin >> s >> t >> x >> y;
}
sort(checkpoint + 1, checkpoint + m + 1);
dfs(1, 0);
// FOR_UP (i, 1, n) {
// cout << i << ' ' << tin[i] << ' ' << tout[i] << endl;
// }
FOR_UP (i, 1, q) L[i] = 0, R[i] = m, ans[i] = -1;
FOR_UP (_, LG) {
silver.init(n); gold.init(n);
FOR_UP (i, 0, m) M[i].clear();
FOR_UP (i, 1, q) {
if (L[i] > R[i]) continue;
int mid = (L[i] + R[i]) >> 1;
M[mid].push_back(i);
}
FOR_UP (i, 1, m) {
auto [c, p] = checkpoint[i];
auto [u, v] = edge[p];
if (tin[u] > tin[v]) swap(u, v);
gold.update_range(tin[v], tout[v], 1);
}
FOR_UP (i, 0, m) {
if (i > 0) {
auto [c, p] = checkpoint[i];
auto [u, v] = edge[p];
if (tin[u] > tin[v]) swap(u, v);
gold.update_range(tin[v], tout[v], -1);
silver.update_range(tin[v], tout[v], c);
}
for (int qID: M[i]) {
auto [s, t, x, y] = query[qID];
if (goldPath(s, t) <= x && silverPath(s, t) <= y) {
ans[qID] = x - goldPath(s, t);
L[qID] = i + 1;
}
else if (goldPath(s, t) > x) {
L[qID] = i + 1;
}
else {
R[qID] = i - 1;
}
}
}
}
FOR_UP (i, 1, q) {
cout << ans[i] << '\n';
}
}
