//Huyduocdithitp
#include <bits/stdc++.h>
typedef long long ll;
#define endl '\n'
#define yes cout<<"YES"<<endl;
#define no cout<<"NO"<<endl;
#define fi first
#define se second
#define pii pair<ll, ll>
#define inf 1e18
#define faster ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MP make_pair
#define TASK "ghuy4g"
#define start if(fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin);freopen(TASK".out","w",stdout);}
#define LOG 19
#define N 100005
using namespace std;
bool ghuy4g;
struct Canh {
ll u, v;
} canh[N];
struct QR {
ll s, t, x, y;
} qr[N];
ll n, m, q, in[N + 1], out[N + 1], par[N + 1][LOG + 2], sz[N + 1], f[N + 1];
ll high[N + 1];
ll bit[N + 1], bit1[N + 1];
vector<ll> adj[N + 1];
pii p[N + 1];
ll timer = 0;
void prepare() {
for (int j = 1; j <= LOG; j ++) {
for (int i = 1; i <= n; i ++) {
ll p = par[i][j - 1];
if (p != 0) par[i][j] = par[p][j - 1];
}
}
}
ll lca(ll u, ll v) {
if (high[u] < high[v]) swap(u, v);
for (int j = LOG; j >= 0; j --) {
if (par[u][j] != 0 && high[u] - (1 << j) >= high[v]) {
u = par[u][j];
}
}
if (u == v) return u;
for (int j = LOG; j >= 0; j --) {
if (par[u][j] != 0 && par[v][j] != 0 && par[u][j] != par[v][j]) {
u = par[u][j];
v = par[v][j];
}
}
return par[u][0];
}
void update(ll u, ll v) {
auto bit_update = [&](ll b[], int idx, ll val) {
for (; idx <= n; idx += idx & -idx) {
b[idx] += val;
}
};
bit_update(bit, in[u], v);
bit_update(bit, out[u] + 1, -v);
bit_update(bit1, in[u], 1);
bit_update(bit1, out[u] + 1, -1);
}
ll get(ll u, ll v) {
auto bit_query = [&](ll b[], int idx) {
ll sum = 0;
for (; idx > 0; idx -= idx & -idx) {
sum += b[idx];
}
return sum;
};
int w = lca(u, v);
return bit_query(bit, in[u]) + bit_query(bit, in[v]) - 2 * bit_query(bit, in[w]);
}
ll get1(ll u, ll v) {
auto bit_query = [&](ll b[], int idx) {
ll sum = 0;
for (; idx > 0; idx -= idx & -idx) {
sum += b[idx];
}
return sum;
};
int w = lca(u, v);
return bit_query(bit1, in[u]) + bit_query(bit1, in[v]) - 2 * bit_query(bit1, in[w]);
}
void dfs1(ll u, ll parent) {
for (auto v : adj[u]) {
if (v == parent) continue;
f[v] += f[u];
dfs1(v, u);
}
}
void dfs(ll u, ll parent, ll h) {
in[u] = ++timer;
par[u][0] = parent;
high[u] = h;
sz[u] = 1;
for (auto v : adj[u]) {
if (v == parent) continue;
dfs(v, u, h + 1);
sz[u] += sz[v];
}
out[u] = timer;
}
ll L[N], R[N], ans[N], kq[N], cnt[N];
bool cmp2(pii a, pii b) {
return a.se < b.se;
}
void solve() {
for (int i = 1; i <= q; i ++) {
L[i] = 0, R[i] = m; ans[i] = -1;
}
sort(p + 1, p + 1 + m, cmp2);
bool flag = 1;
ll turn =0;
while (flag) {
turn ++ ;
//cout << "turn: " << turn << endl;
flag = 0;
vector<ll> bucket[m + 2];
memset(bit, 0, sizeof(bit));
memset(bit1, 0, sizeof(bit1));
for (int i = 1; i <= q; i ++) {
if (L[i] <= R[i]) {
flag = 1;
ll mid = (L[i] + R[i]) / 2;
bucket[mid].push_back(i);
//cout << "b " << mid << " " << i << " LR " << L[i] << " " << R[i] << " " << ans[i] << endl;
}
}
if (!flag) break;
for (int i = 0; i <= m; i ++) {
if (i > 0) {
ll edge_index = p[i].fi;
ll child_node = canh[edge_index].v;
ll weight = p[i].se;
update(child_node, weight);
//cout << "upd " << child_node << " " << weight << endl;
}
for (auto it : bucket[i]) {
ll u = qr[it].s, v = qr[it].t;
if (get(u, v) <= qr[it].y) {
ans[it] = i;
L[it] = i + 1;
kq[it] = get1(u, v);
}
else {
R[it] = i - 1;
}
}
}
}
for (int i = 1; i <= q; i ++) {
//cout << i << " " << ans[i] << " " << kq[i] << " " << cnt[i] << " " << qr[i].x << endl;
ll dungvang = cnt[i] - kq[i]; // cai nay mini
ll left = qr[i].x - dungvang;
if (left < 0) {
left = -1;
}
cout << left << endl;
}
}
bool klinh;
signed main(void) {
faster;
cin >> n >> m >> q;
for (int i = 1; i <= n - 1; i ++) {
cin >> canh[i].u >> canh[i].v;
}
for (int i = 1; i <= m; i ++) {
ll s, t;
cin >> s >> t;
p[i] = {s, t};
}
for (int i = 1; i <= n - 1; i ++) {
ll u = canh[i].u, v = canh[i].v;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1, 0, 0);
prepare();
for (int i = 1; i < n; i++) {
if(par[canh[i].u][0] == canh[i].v) {
swap(canh[i].u, canh[i].v);
}
}
for (int i = 1; i <= m; i ++) {
ll s = p[i].fi;
f[canh[s].v]++;
//cout << canh[s].v << endl;
}
dfs1(1, 0);
for (int i = 1; i <= q; i ++) {
cin >> qr[i].s >> qr[i].t >> qr[i].x >> qr[i].y;
cnt[i] = f[qr[i].s] + f[qr[i].t] - 2 * f[lca(qr[i].s, qr[i].t)];
}
solve();
cerr << fabs(&klinh - &ghuy4g) / 1048576.0;
return 0;
}
