#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 1e5 + 5;
vector<int> g[maxn];
pair<int, int> edge[maxn], sta[maxn];
vector<int> res[maxn];
int s[maxn], t[maxn], w[maxn];
int G[maxn], S[maxn], bit[maxn];
void update(int p, int val){
for(; p < maxn; p += p & -p) bit[p] += val;
}
int get(int p){
int res = 0;
for(; p; p -= p & -p) res += bit[p];
return res;
}
//for HLD
int nxt[maxn], head[maxn], sz[maxn], par[maxn], h[maxn];
int tin[maxn], out[maxn], timedfs;
void dfs(int u, int p){
sz[u] = 1;
for(int v: g[u]){
if(v == p) continue;
par[v] = u;
h[v] = h[u] + 1;
dfs(v, u);
sz[u] += sz[v];
if(sz[nxt[u]] < sz[v]) nxt[u] = v;
}
}
void hld(int u, int p, int cur){
tin[u] = ++timedfs;
head[u] = cur;
if(nxt[u]) hld(nxt[u], u, cur);
for(int v: g[u]){
if(v == p || v == nxt[u]) continue;
hld(v, u, v);
}
out[u] = timedfs;
}
int path(int u, int v){
int ans = 0;
while(head[u] != head[v]){
if(h[head[u]] < h[head[v]]) swap(u, v);
ans += get(tin[u]) - get(tin[head[u]] - 1);
u = par[head[u]];
}
if(h[u] > h[v]) swap(u, v);
ans += get(tin[v]) - get(tin[u]);
return ans;
}
//for PBS
int L[maxn], R[maxn], ans[maxn];
vector<int> query[maxn];
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, m, q; cin >> n >> m >> q;
for(int i = 1; i <= n - 1; i++){
int u, v; cin >> u >> v;
edge[i] = {u, v};
g[u].push_back(v);
g[v].push_back(u);
}
dfs(1, -1);
hld(1, -1, 1);
//di qua ton 1 G hoac c S
for(int i = 1; i <= m; i++){
int id, c; cin >> id >> c;
auto [u, v] = edge[id];
if(h[u] > h[v]) swap(u, v);
sta[i] = {c, v};
}
//sort lai c
sort(sta + 1, sta + 1 + m);
//tinh so G toi da giu lai duoc
for(int i = 1; i <= q; i++) cin >> s[i] >> t[i] >> G[i] >> S[i];
for(int i = 1; i <= q; i++) L[i] = 1, R[i] = m;
for(int loop = 1; loop <= 17; loop++){
memset(bit, 0, sizeof(bit));
for(int i = 1; i <= q; i++) if(L[i] <= R[i]) query[(L[i] + R[i]) / 2].push_back(i);
for(int mid = 1; mid <= m; mid++){
auto [cost, u] = sta[mid];
update(tin[u], cost);
for(int i: query[mid]){
if(path(s[i], t[i]) <= S[i]) L[i] = mid + 1, ans[i] = mid;
else R[i] = mid - 1;
}
query[mid].clear();
}
}
for(int i = 1; i <= q; i++) res[ans[i]].push_back(i);
memset(bit, 0, sizeof(bit));
for(int i = 1; i <= m; i++){
update(tin[sta[i].second], 1);
for(int v: res[i]) w[v] = path(s[v], t[v]); //sl cua hang di qua nhieu nhat bang silver
}
for(int i = 1; i <= q; i++){
int cost = path(s[i], t[i]);
if(cost - w[i] <= G[i]) cout << G[i] - cost + w[i] << '\n';
else cout << -1 << '\n';
}
}
