#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MAXN = 200000;
int N, M, Q;
vector<pair<int,int>> adj[MAXN+1];
int U[MAXN+1], V[MAXN+1];
int parent_[MAXN+1], depth[MAXN+1], heavy[MAXN+1], sz[MAXN+1];
int head[MAXN+1], pos[MAXN+1], curPos;
int edgeIdAtNode[MAXN+1];
vector<ll> allC;
int rootAtNode[MAXN+1];
struct Node {
int l, r;
int cnt;
ll sum;
} seg[MAXN * 40];
int segCnt = 0;
int build(int nl,int nr){
int id = ++segCnt;
seg[id].l = seg[id].r = 0;
seg[id].cnt = seg[id].sum = 0;
if(nl < nr){
int m = (nl+nr)>>1;
seg[id].l = build(nl,m);
seg[id].r = build(m+1,nr);
}
return id;
}
int update(int old,int nl,int nr,int pos){
int id = ++segCnt;
seg[id] = seg[old];
if(nl==nr){
seg[id].cnt += 1;
seg[id].sum += allC[nl-1];
} else {
int m=(nl+nr)>>1;
if(pos<=m) seg[id].l = update(seg[old].l, nl,m,pos);
else seg[id].r = update(seg[old].r, m+1,nr,pos);
seg[id].cnt = seg[ seg[id].l ].cnt + seg[ seg[id].r ].cnt;
seg[id].sum = seg[ seg[id].l ].sum + seg[ seg[id].r ].sum;
}
return id;
}
ll query_kth_sum(int a,int b,int c,int d,int nl,int nr,int k){
if(k<=0) return 0;
if(nl==nr){
return allC[nl-1] * 1LL * k;
}
int cntL = seg[ seg[a].l ].cnt
+ seg[ seg[b].l ].cnt
- seg[ seg[c].l ].cnt
- seg[ seg[d].l ].cnt;
int m=(nl+nr)>>1;
if(k <= cntL){
return query_kth_sum(seg[a].l, seg[b].l, seg[c].l, seg[d].l,
nl, m, k);
} else {
ll sumL = seg[ seg[a].l ].sum
+ seg[ seg[b].l ].sum
- seg[ seg[c].l ].sum
- seg[ seg[d].l ].sum;
return sumL
+ query_kth_sum(seg[a].r, seg[b].r, seg[c].r, seg[d].r,
m+1, nr, k - cntL);
}
}
vector<vector<int>> atChecksOnEdge;
int dfs1(int u,int p){
parent_[u]=p;
depth[u]=(p==0?0:depth[p]+1);
sz[u]=1; heavy[u]=0;
for(auto &e:adj[u]){
int v=e.first, ei=e.second;
if(v==p) continue;
edgeIdAtNode[v]=ei;
int s = dfs1(v,u);
sz[u]+=s;
if(s > sz[ heavy[u] ]) heavy[u]=v;
}
return sz[u];
}
void dfs2(int u,int h){
head[u]=h;
pos[u]=++curPos;
rootAtNode[u] = (u==1? rootAtNode[1] : rootAtNode[parent_[u]]);
for(int cc: atChecksOnEdge[ edgeIdAtNode[u] ]) {
rootAtNode[u] = update(rootAtNode[u], 1, M, cc);
}
if(heavy[u]) dfs2(heavy[u], h);
for(auto &e:adj[u]){
int v=e.first;
if(v==parent_[u] || v==heavy[u]) continue;
dfs2(v, v);
}
}
int lca(int a,int b){
while(head[a]!=head[b]){
if(depth[ head[a] ] > depth[ head[b] ])
a = parent_[ head[a] ];
else
b = parent_[ head[b] ];
}
return depth[a]<depth[b]? a:b;
}
void path_roots(int u,int v, int &ru, int &rv, int &rlca, int &rplca){
int w = lca(u,v);
ru = rootAtNode[u];
rv = rootAtNode[v];
rlca = rootAtNode[w];
int pw = parent_[w];
rplca = (pw==0? 0 : rootAtNode[pw]);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N >> M >> Q;
for(int i=1;i<N;i++){
cin >> U[i] >> V[i];
adj[U[i]].push_back({V[i],i});
adj[V[i]].push_back({U[i],i});
}
vector<pair<int,ll>> checks(M);
for(int i=0;i<M;i++){
cin >> checks[i].first >> checks[i].second;
allC.push_back(checks[i].second);
}
sort(allC.begin(), allC.end());
allC.erase(unique(allC.begin(), allC.end()), allC.end());
atChecksOnEdge.assign(N+1, {});
for(auto &p:checks){
int eidx = p.first;
ll c = p.second;
int cc = int(lower_bound(allC.begin(), allC.end(), c) - allC.begin()) + 1;
atChecksOnEdge[eidx].push_back(cc);
}
dfs1(1,0);
rootAtNode[1] = build(1, M);
dfs2(1,1);
while(Q--){
int s,t;
ll X,Y;
cin >> s >> t >> X >> Y;
int ru,rv,rlca,rplca;
path_roots(s,t, ru,rv,rlca,rplca);
int totCnt = seg[ru].cnt + seg[rv].cnt - seg[rlca].cnt - seg[rplca].cnt;
int lo=0, hi=totCnt, best=0;
while(lo<=hi){
int mid = (lo+hi)/2;
ll sumK = query_kth_sum(ru,rv,rlca,rplca, 1,M, mid);
if(sumK <= Y){
best = mid;
lo = mid+1;
} else {
hi = mid-1;
}
}
int silverPaid = best;
int goldNeeded = totCnt - silverPaid;
if(goldNeeded > X) cout << -1 << "\n";
else cout << (X - goldNeeded) << "\n";
}
return 0;
}
