#include <bits/stdc++.h>
using namespace std;
#define int long long
const int NM = 1e5, LOG = 16;
struct checkpt{
int v, c;
};
struct query{
int id, s, t, lca, x, y, l, r, mid, res;
};
int N, M, Q, u[NM+5], v[NM+5], t = 0;
vector <int> adj[NM+5];
int parent[NM+5], h[NM+5], st[NM+5], en[NM+5];
int jump[NM+5][LOG+5];
checkpt a[NM+5];
query b[NM+5];
int bit[2*NM+5], bit2[2*NM+5];
int ans[NM+5];
void DFS(int u){
st[u] = ++t;
for (int i = 0; i < adj[u].size(); i++){
int v = adj[u][i];
if (h[v] != -1) continue;
parent[v] = u;
h[v] = h[u]+1;
DFS(v);
}
en[u] = ++t;
}
void build(){
for (int i = 1; i <= N; i++) jump[i][0] = parent[i];
for (int j = 1; j <= LOG; j++)
for (int i = 1; i <= N; i++)
if (jump[i][j-1] != -1) jump[i][j] = jump[jump[i][j-1]][j-1];
else jump[i][j] = -1;
}
int LCA(int u, int v){
if (h[u] < h[v]) swap(u, v);
for (int i = LOG; i >= 0; i--)
if (h[u]-(1<<i) >= h[v]) u = jump[u][i];
if (u == v) return u;
for (int i = LOG; i >= 0; i--)
if (jump[u][i] != -1 && jump[u][i] != jump[v][i]){
u = jump[u][i];
v = jump[v][i];
}
return parent[u];
}
bool cmp(checkpt a, checkpt b){
return a.c < b.c;
}
bool cmp2(query a, query b){
if (a.l > a.r) return 0;
if (b.l > b.r) return 1;
return a.mid < b.mid;
}
void update(int bit[NM+5], int p, int v){
while (p <= 2*N){
bit[p] += v;
p += p & (-p);
}
}
int get(int bit[NM+5], int p){
int res = 0;
while (p > 0){
res += bit[p];
p -= p & (-p);
}
return res;
}
int get_range(int bit[NM+5], int l, int r){
return get(bit, r)-get(bit, l-1);
}
int get_path(int bit[NM+5], int s, int t, int lca){
return get_range(bit, st[lca], st[s])+get_range(bit, st[lca], st[t])-2*get_range(bit, st[lca], st[lca]);
}
void pbs(){
sort(b+1, b+1+Q, cmp2);
memset(bit, 0, sizeof(bit));
memset(bit2, 0, sizeof(bit2));
for (int i = 1; i <= M; i++){
update(bit, st[a[i].v], 1);
update(bit, en[a[i].v], -1);
}
int j = 1;
for (int i = 1; i <= Q; i++){
if (b[i].l > b[i].r) break;
while (j <= b[i].mid){
update(bit, st[a[j].v], -1);
update(bit, en[a[j].v], 1);
update(bit2, st[a[j].v], a[j].c);
update(bit2, en[a[j].v], -a[j].c);
j++;
}
int tmp = get_path(bit2, b[i].s, b[i].t, b[i].lca);
if (tmp <= b[i].y){
b[i].res = get_path(bit, b[i].s, b[i].t, b[i].lca);
b[i].l = b[i].mid+1;
}
else b[i].r = b[i].mid-1;
b[i].mid = (b[i].l+b[i].r)/2;
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> M >> Q;
for (int i = 1; i < N; i++){
cin >> u[i] >> v[i];
adj[u[i]].push_back(v[i]);
adj[v[i]].push_back(u[i]);
}
parent[1] = -1, h[1] = 0;
for (int i = 2; i <= N; i++) h[i] = -1;
DFS(1);
build();
for (int i = 1; i <= M; i++){
int p; cin >> p;
if (parent[v[p]] == u[p]) a[i].v = v[p]; else a[i].v = u[p];
cin >> a[i].c;
}
sort(a+1, a+1+M, cmp);
for (int i = 1; i <= Q; i++){
b[i].id = i;
cin >> b[i].s >> b[i].t >> b[i].x >> b[i].y;
if (st[b[i].s] > st[b[i].t]) swap(b[i].s, b[i].t);
b[i].lca = LCA(b[i].s, b[i].t);
b[i].l = 0, b[i].r = M, b[i].mid = M/2;
}
for (int i = 0; (1<<i) <= M+1; i++)
pbs();
for (int i = 1; i <= Q; i++){
if (b[i].res > b[i].x) ans[b[i].id] = -1;
else ans[b[i].id] = b[i].x-b[i].res;
}
for (int i = 1; i <= Q; i++) cout << ans[i] << '\n';
return 0;
}
