#include <bits/stdc++.h>
#define se second
#define fs first
#define mp make_pair
#define pb push_back
#define ll long long
#define ii pair<ll,ll>
#define ld long double
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(), v.end()
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now().time_since_epoch().count());
ll Rand(ll l, ll r)
{
return uniform_int_distribution<ll> (l, r)(rd);
}
const int N = 1e5 + 7;
const int Mod =1e9 + 7;
const int szBL = 916;
const int INF = 2e9 + 7;
const int BASE = 137;
int n, m, Q;
int a[N];
vector<int> ke[N];
pair<int,int> edg[N];
pair<ll,ll> b[N];
int high[N], pa[N][25];
int nChild[N], in[N], Head[N], par[N], nChain = 1, chainId[N];
struct Persistent_Segment_Tree {
int Range;
struct Node {
Node *lc, *rc;
ll sum, cnt;
Node (int sum = 0, int cnt = 0) : lc(nullptr), rc (nullptr), sum(sum), cnt(cnt) {};
Node (Node *lc, Node *rc) : lc(lc), rc(rc), sum(0), cnt(0) {
sum += lc->sum, cnt += lc->cnt;
sum += rc->sum, cnt += rc->cnt;
}
}*ver[N];
Node *build (int l, int r) {
if (l == r) return new Node (0, 0);
int mid = l + r >> 1;
return new Node (build (l, mid), build (mid +1 , r));
}
void init (int n) {
Range = n;
ver[0] = build (1, Range);
}
Node *update (Node *cur, int l, int r, int pos, ll val) {
if (l == r) {
return new Node (cur->sum + val, cur->cnt + 1);
}
int mid = l + r >> 1;
if (pos <= mid)
return new Node (update (cur->lc, l, mid, pos, val), cur->rc);
else
return new Node (cur->lc, update (cur->rc, mid + 1, r, pos, val));
}
pair<ll, ll> get (Node *cur, int l, int r, int u, int v) {
if (u > v) return mp(0, 0);
if (l > v || r < u) return mp(0, 0);
if (l >= u && r <= v)
return mp(cur->sum, cur->cnt);
int mid = l + r >> 1;
pair<ll,ll> p1 = get(cur->lc, l, mid, u, v);
pair<ll,ll> p2 = get(cur->rc, mid + 1, r, u, v);
return mp(p1.fs + p2.fs, p1.se + p2.se);
}
void update (int pos, ll val) {
static int nver = 0;
++nver;
ver[nver] = update (ver[nver - 1], 1, Range, pos, val);
}
pair<ll, ll> get (int u, int v, int vr) {
return get (ver[vr], 1, Range, u, v);
}
}ST;
void pdfs (int u, int p) {
nChild[u] = 1;
pa[u][0] = par[u] = p;
high[u] = high[p] + 1;
rep (i, 1, 20) pa[u][i] = pa[pa[u][i - 1]][i - 1];
iter (&v, ke[u]) {
if (v != p) {
pdfs(v, u);
nChild[u] += nChild[v];
}
}
}
void hld (int u, int p) {
static int time_dfs = 0;
if (nChain != chainId[p]) Head[u] = u;
else Head[u] = Head[p];
chainId[u] = nChain;
in[u] = ++time_dfs;
int mxV = -1;
iter (&v, ke[u]) {
if (v != p && (mxV == -1 || nChild[v] > nChild[mxV])) {
mxV = v;
}
}
// cout << u <<" "<<Head[u] <<" "<<in[u] <<"\n";
if (mxV != -1) hld (mxV, u);
iter (&v, ke[u]) {
if (v == p || v == mxV) continue;
++nChain;
hld (v, u);
}
}
int Lca (int u, int v) {
if (high[u] > high[v]) swap (u, v);
int delta = high[v] - high[u];
rep (i, 0, 20) if (bit(delta, i)) {
v = pa[v][i];
}
if (v == u) return u;
reb (i, 20, 0) {
if (pa[v][i] != pa[u][i]) {
v = pa[v][i];
u = pa[u][i];
}
}
return pa[u][0];
}
int Dist (int u, int v) {
return high[u] + high[v] - 2 * high[Lca(u, v)];
}
pair<ll,ll> get (int u, int v, int ver) {
ll sum = 0, cnt = 0;
for (; Head[u] != Head[v]; v = par[Head[v]]) {
if (high[Head[u]] > high[Head[v]]) swap (u, v);
pair<ll,ll> cur = ST.get (in[Head[v]], in[v], ver);
sum += cur.fs;
cnt += cur.se;
// cout << Head[v] <<" "<<v<<" "<<cur.fs<<" "<<cur.se<<"\n";
}
if (high[u] > high[v]) swap (u, v);
pair<ll,ll> cur = ST.get (in[u] + 1, in[v], ver);
sum += cur.fs;
cnt += cur.se;
// cout << u <<" "<<v<<" "<<cur.fs<<" "<<cur.se<<"\n";
return mp (sum, cnt);
}
void solution () {
cin >> n >> m >> Q;
rep (i, 1, n - 1) {
int u, v;
cin >> u >> v;
ke[u].push_back(v);
ke[v].push_back(u);
edg[i] = {u, v};
}
pdfs (1, 0);
hld (1, 0);
rep (i, 1, m) {
ll id, val;
cin >> id >> val;
if (par[edg[id].fs] != edg[id].se) swap(edg[id].fs, edg[id].se);
b[i] = {edg[id].fs, val};
}
sort (b + 1, b + 1 + m, [] (pair<ll,ll> A, pair<ll,ll> B) { return A.se < B.se; });
ST.init(n);
rep (i, 1, m) {
ST.update (in[b[i].fs], b[i].se);
// cout << in[b[i].fs]<<","<<b[i].se<<" "<<ST.get(
}
// cout << ST.get(5, 5, m).fs <<"\n";
// return;
rep (i, 1, Q) {
int u, v;
ll X, Y;
cin >> u >> v >> X >> Y;
int lf = 0, rt = m;
while (lf < rt) {
int mid = lf + rt + 1 >> 1;
if (get(u, v, mid).fs <= Y) lf= mid;
else rt= mid - 1;
}
pair<ll,ll> cur = get(u, v, lf);
// cout << lf <<" "<<cur.fs<<" "<<cur.se<<"\n";
if (cur.fs <= Y && get(u, v, m).se - cur.se <= X) {
cout << X - (get(u, v, m).se - cur.se) <<"\n";
}
else cout <<-1 <<"\n";
}
}
#define file(name) freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);
int main () {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// file ("c");
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
1 2
*/
