#include <bits/stdc++.h>
using namespace std;
#define int long long
struct node {
int val1, val2, lpt, rpt;
};
const int maxn = 1e5 + 5, lgn = 18, maxN = 4e5 + 5;
int n, m, q;
vector<pair<int,int>> adj[maxn];
vector<int> ck[maxn];
int fa[maxn], sz[maxn], d[maxn];
pair<int,int> a[maxn];
bool cmp(pair<int,int> x, pair<int,int> y) {
return sz[x.first] > sz[y.first];
}
void dfs1(int u) {
for (auto [v, id]:adj[u]) {
adj[v].erase(find(adj[v].begin(), adj[v].end(), make_pair(u, id)));
fa[v] = u, sz[v] = ck[id].size(), d[v] = d[u]+1;
dfs1(v);
sz[u] += sz[u];
}
sort(adj[u].begin(), adj[u].end(), cmp);
}
int newid[maxn], cnter = 1;
void dfs2(int u) {
for (auto [v, id]:adj[u]) {
for (auto &j:ck[id]) j = newid[j] = cnter++;
dfs2(v);
}
}
pair<int, vector<pair<int,int>>> lift[maxn][lgn];
void dfs3(int u) {
for (int i=1;i<lgn;i++) {
if (lift[u][i-1].first==-1 || lift[lift[u][i-1].first][i-1].first==-1) break;
lift[u][i].first = lift[lift[u][i-1].first][i-1].first;
lift[u][i].second = lift[u][i-1].second;
for (auto [l, r]:lift[lift[u][i-1].first][i-1].second) {
if (lift[u][i].second.size()>0 && r+1 == lift[u][i].second.back().first) lift[u][i].second.back().first = l;
else lift[u][i].second.push_back({l, r});
}
}
for (auto [v, id]:adj[u]) {
lift[v][0].first = u;
if (ck[id].size()!=0) lift[v][0].second.push_back({ck[id][0], ck[id].back()});
dfs3(v);
}
}
vector<node> seg[maxN];
void build(int id, int l, int r) {
seg[id] = {{0, 0, 0, 0}};
if (l==r) return;
int mid = (l+r)/2;
build(id*2, l, mid);
build(id*2+1, mid+1, r);
}
void update(int id, int l, int r, int target, int val1, int val2) {
if (r<target || target<l) return;
if (l==r) {
seg[id].push_back({val1, val2, -1, -1});
return;
}
int mid = (l+r)/2;
update(id*2, l, mid, target, val1, val2); update(id*2+1, mid+1, r, target, val1, val2);
node nxt = {0, 0, (int)seg[id*2].size()-1, (int)seg[id*2+1].size()-1};
nxt.val1 = seg[id*2].back().val1 + seg[id*2+1].back().val1;
nxt.val2 = seg[id*2].back().val2 + seg[id*2+1].back().val2;
seg[id].push_back(nxt);
}
pair<int,int> qry(int id, int pt, int l, int r, int findl, int findr) {
if (findl<=l && r<=findr) return {seg[id][pt].val1, seg[id][pt].val2};
if (r<findl || findr<l) return {0, 0};
int mid = (l+r)/2, lpt = seg[id][pt].lpt, rpt = seg[id][pt].rpt;
pair<int,int> lhs = qry(id*2, lpt, l, mid, findl, findr);
pair<int,int> rhs = qry(id*2+1, rpt, mid+1, r, findl, findr);
return {lhs.first + rhs.first, lhs.second + rhs.second};
}
vector<pair<int,int>> qry2(int u, int v) {
if (d[u] > d[v]) swap(u, v);
vector<pair<int,int>> U, V;
for (int i=lgn-1;i>=0;i--) if (d[v] - (1<<i) >= d[u]) {
for (auto [l, r]:lift[v][i].second) {
if (V.size() > 0 && r+1 == V.back().first) V.back().first = l;
else V.push_back({l, r});
}
v = lift[v][i].first;
}
if (u==v) return V;
for (int i=lgn-1;i>=0;i--) if (lift[u][i].first!=lift[v][i].first) {
for (auto [l, r]:lift[u][i].second) {
if (U.size() > 0 && r+1 == U.back().first) U.back().first = l;
else U.push_back({l, r});
}
for (auto [l, r]:lift[v][i].second) {
if (V.size() > 0 && r+1 == V.back().first) V.back().first = l;
else V.push_back({l, r});
}
u = lift[u][i].first, v = lift[v][i].first;
}
for (auto [l, r]:lift[u][0].second) {
if (U.size() > 0 && r+1 == U.back().first) U.back().first = l;
else U.push_back({l, r});
}
for (auto [l, r]:lift[v][0].second) {
if (V.size() > 0 && r+1 == V.back().first) V.back().first = l;
else V.push_back({l, r});
}
for (auto [l, r]:V) U.push_back({l, r});
return U;
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n >> m >> q;
for (int i=1;i<n;i++) {
int u, v;
cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
int A[m+1];
for (int i=1;i<=m;i++) {
int loc;
cin >> loc >> A[i];
ck[loc].push_back(i);
}
for (int i=1;i<=n;i++) fa[i] = -2;
fa[1] = -1, sz[1] = 0, d[1] = 0;
dfs1(1);
dfs2(1);
// for (int i=1;i<=m;i++) cout << newid[i] << " "; cout << endl;
for (int i=1;i<=m;i++) a[newid[i]] = {A[i], newid[i]};
for (int i=1;i<=n;i++) for (int j=0;j<lgn;j++) lift[i][j] = {-1, {}};
dfs3(1);
sort(a+1, a+m+1);
build(1, 1, m);
for (int i=1;i<=m;i++) update(1, 1, m, a[i].second, a[i].first, 1);
// for (int i=1;i<=n;i++) {
// cout << i << endl;
// for (auto [l, r]:lift[i][0].second) cout << l << " " << r << endl;
// cout << endl;
// }
// cout << "test" << endl;
while (q--) {
int u, v, x, y;
cin >> u >> v >> x >> y;
vector<pair<int,int>> vec = qry2(u, v);
// for (auto [l, r]:vec) cout << l << " " << r << endl;
int L = 0, R = m;
while (L<R) {
int mid = (L+R+1)/2, sum = 0;
for (auto [l, r]:vec) sum += qry(1, mid, 1, m, l, r).first;
if (sum > y) R = mid-1;
else L = mid;
}
int sum = 0;
for (auto [l, r]:vec) sum += qry(1, m, 1, m, l, r).second - qry(1, L, 1, m, l, r).second;
x -= sum;
if (x<0) cout << -1 << "\n";
else cout << x << "\n";
}
}
