#include <bits/stdc++.h>
// #pragma GCC optimize("O3")
#define int long long
#define ll long long
#define se second
#define fi first
#define pb push_back
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii,pii> ipii;
const int MAXN = 1e5+10;
const int SQRT = 450;
const int INF = 2e9;
const int MOD = 998244353;
const int LOG = 20;
int sum(int a, int b){ a%=MOD; b%=MOD; return (a+MOD+b)%MOD; }
void chsum(int &a, int b){ a%=MOD; b%=MOD; a = (a+MOD+b)%MOD; }
int mul(int a, int b){ return (a*b)%MOD; }
int expo(int a, int b){
if(b==0) return 1;
int te = expo(a, b/2); te = mul(te,te);
return (b%2 ? mul(te,a) : te);
}
void chmul(int &a, int b){ a = (a*b)%MOD; }
void chmn(auto &a, auto b){ a = min(a, b); }
void chmx(auto &a, auto b){ a = max(a, b); }
int n, m, q;
int ans[MAXN], u[MAXN], v[MAXN];
int idx[MAXN], co[MAXN], s[MAXN], t[MAXN], x[MAXN], y[MAXN];
struct fen {
pii st[MAXN];
void bd(){
for(int i=0; i<=MAXN-10; i++) st[i] = {0, 0};
}
pii que(int x){
pii te = {0, 0};
for(; x; x-=x&-x) te.fi += st[x].fi, te.se += st[x].se;
return te;
}
void upd(int x, pii p){
for(; x<=MAXN-10; x+=x&-x) st[x].fi += p.fi, st[x].se += p.se;
}
} A;
vector<array<int,3>> cek[MAXN];
int cnt[MAXN][4], point[MAXN];
int pr[MAXN];
vector<int> adj[MAXN], tree[MAXN];
int sub[MAXN], root[MAXN], dep[MAXN], par[MAXN], tim[MAXN], day;
void trav(int nw, int pa){
for(auto nx : tree[nw]){
if(nx==pa) continue;
adj[nw].pb(nx);
trav(nx,nw);
}
}
void dfs(int nw, int pa){
sub[nw] = 1; dep[nw] = dep[pa]+1; par[nw] = pa;
for(auto nx : adj[nw]){
dfs(nx, nw); sub[nw] += sub[nx];
}
}
void bd(int nw, int roo){
tim[nw] = ++day;
root[nw] = roo;
if(adj[nw].empty()) return;
bd(adj[nw][0], roo);
for(int i=1; i<adj[nw].size(); i++)
bd(adj[nw][i], adj[nw][i]);
}
pii GET(int x, int y){
if(x < y) assert(false);
pii t1 = A.que(x), t2 = A.que(y);
pii ret = pii(t1.fi-t2.fi, t1.se-t2.se);
return ret;
}
pii hld(int x, int y){
pii tot = {0, 0};
while(root[x] != root[y]){
if(dep[root[x]] > dep[root[y]]) swap(x, y);
// gerak y ke root
// mau dpt node y ke root[y]
pii que = GET(tim[y], tim[root[y]]-1); // bawah ke atas
// cout << y << ' ' << root[y] << ' ' << que.fi<<' '<<que.se<<" root\n";
tot.fi += que.fi; tot.se += que.se;
y = par[root[y]];
}
if(dep[x] > dep[y]) swap(x, y);
if(x != y){
// dr node y ke bawahnya x
// cout << tim[y] <<' '<<tim[x] << " tim\n";
pii que = GET(tim[y], tim[x]); // bawah ke atas
tot.fi += que.fi; tot.se += que.se;
// cout << y << ' ' << x << ' ' << que.fi << ' '<< que.se << " terakhir\n";
}
return tot;
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n>>m>>q;
for(int i=1; i<=n-1; i++){
cin>>u[i]>>v[i];
tree[u[i]].pb(v[i]); tree[v[i]].pb(u[i]);
}
trav(1, 0);
dfs(1, 0);
for(int i=1; i<=n; i++){
if(adj[i].empty()) continue;
for(int j=1; j<adj[i].size(); j++)
if(sub[ adj[i][0] ] < sub[ adj[i][j] ])
swap(adj[i][0], adj[i][j]);
}
bd(1, 1);
for(int i=1; i<=n-1; i++){
if(dep[ u[i] ] > dep[ v[i] ]) swap(u[i], v[i]);
}
vector<int> cc; cc.pb(-1);
for(int i=1; i<=m; i++){
cin>>idx[i]>>co[i];
cc.pb(co[i]);
}
sort(cc.begin(), cc.end());
cc.resize(unique(cc.begin(), cc.end())-cc.begin());
int siz = cc.size()-1;
vector<pii> edge; edge.pb({-1,-1});
for(int i=1; i<=m; i++){
co[i] = lower_bound(cc.begin(), cc.end(), co[i])-cc.begin();
edge.pb({co[i], idx[i]});
}
sort(edge.begin(), edge.end());
for(int i=1; i<=q; i++){
cin>>s[i]>>t[i]>>x[i]>>y[i];
cek[(siz+1)/2].pb({1, siz, i});
}
// build point
for(int i=1; i<=m; i++){
int id = edge[i].se; // idx dr edge
id = v[id]; // idx dr node
int cost = cc[ edge[i].fi ];
// cout << id << ' ' << cost << " cost\n";
A.upd(tim[id], pii(cost, 1) );
}
// cout << GET(tim[6], tim[1]).se << " edge\n";
// cout << "here\n";
for(int i=1; i<=q; i++){
int up = s[i], dw = t[i];
// cout << up << ' ' << dw << " up\n";
pii ret = hld(up, dw);
point[i] = ret.se; // lewat brp edge
// cout << i << ' ' << point[i] << " pp\n\n";
}
bool done = 0;
while(!done){
done = 1; A.bd();
int edupd = 1; // edge ter yg blm update
for(int i=1; i<=siz; i++){
// masukin yg costnya = cc[i], cost of unique edge
while(edupd<edge.size() && edge[edupd].fi == i){
int id = edge[edupd].se; // idx dr edge
id = v[id];
A.upd(tim[id], pii(cc[i], 1) );
edupd++;
}
// cout << "masulk\n";
// solve cek(i)
for(auto pp : cek[i]){
auto [l, r, qidx] = pp;
int silv = y[qidx];
int up = s[qidx], dw = t[qidx];
pii ret = hld(up, dw);
// silver, num edge
if(ret.fi <= silv){ // oh bisa
cnt[qidx][0] = i; cnt[qidx][1] = ret.fi;
cnt[qidx][2] = ret.se;
int mid = (i+1+r)>>1;
if(i+1<=r){
cek[mid].pb({i+1, r, qidx}); done = 0;
}
} else {
int mid = (l+i-1)>>1;
if(l<=i-1){
cek[mid].pb({l, i-1, qidx}); done = 0;
}
}
}
cek[i].clear();
}
}
// cout << siz << " unique cost\n";
for(int i=1; i<=q; i++){ // punya y[i]
// cout << i << " i\n";
// cout << cnt[i][0] << ' '<< cnt[i][1] << ' ' << cnt[i][2] << " cnt\n\n";
int ed = cnt[i][2];
if(cnt[i][0]+1 <= siz){
int sis = y[i]-cnt[i][1];
ed += sis/cc[ cnt[i][0]+1 ]; // bisa ambil segini lagi
}
int gold = point[i]-ed;
cout << (gold > x[i] ? -1 : x[i]-gold) << '\n';
}
}
