#include<bits/stdc++.h>
using namespace std;
#define vec vector
#define int long long
const int MXM = 1<<17;
const int MXQ = 100'005;
const int MXN = 1<<17;
#define ptr shared_ptr
struct Node {
ptr<Node> left;
ptr<Node> right;
int sum = 0;
int cnt = 0;
ptr<Node> get_left() {
ptr<Node> res(new Node{});
if(left) *res = *left;
left = res;
return left;
}
ptr<Node> get_right() {
ptr<Node> res(new Node{});
if(right) *res = *right;
right = res;
return right;
}
void update(int l, int r, int add) {
_update(l, r, add, 0, MXN);
}
void _update(int l, int r, int add, int tl, int tr) {
if(tl >= r || tr <= l) {
return;
}
if(tl >= l && tr <= r) {
sum += add;
cnt++;
return;
}
int tm = (tl+tr)/2;
get_left()->_update(l, r, add, tl, tm);
get_right()->_update(l, r, add, tm, tr);
}
pair<int, int> query(int i) {
return _query(i, 0, MXN);
}
void push() {
get_left()->sum += sum;
get_left()->cnt += cnt;
get_right()->sum += sum;
get_right()->cnt += cnt;
sum = 0;
cnt = 0;
}
pair<int, int> _query(int i, int tl, int tr) {
if(tl+1 == tr) {
assert(tl == i);
return {sum, cnt};
}
push();
int tm = (tl+tr)/2;
if(i<tm) {
return get_left()->_query(i, tl, tm);
}
else {
return get_right()->_query(i, tm, tr);
}
}
};
Node pers_st[MXM];
int in[MXN];
int out[MXN];
int depth[MXN];
int jmp[MXN][20];
vec<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;
vec<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);
vec<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());
for(int i = 1; i<=M; i++) {
pers_st[i] = pers_st[i-1];
auto [c, ei] = cs[i-1];
auto [u, v] = edges[ei];
if(depth[u] < depth[v]) swap(u, v);
pers_st[i].update(in[u], out[u], c);
//cerr << "INSERTING: " << in[u] << ' ' << out[u] << ' ' << c << '\n';
}
for(int i = 0; i<Q; i++) {
int u, v, g, s;
cin >> u >> v >> g >> s;
u--;v--;
int w = lca(u, v);
//cerr << u << ' ' << v << ' ' << w << '\n';
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]);
/// << a2 << ' ' << b2 << ' ' << c2 << '\n';
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';
}
}
}
