// author : sentheta aka vanwij
#ifdef VANWIJ
#include"/home/user/code/bits/stdc++.h"
#else
#include"bits/stdc++.h"
#endif
using namespace std;
#define Int long long
#define V vector
#define pii pair<int,int>
#define ff first
#define ss second
static mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pow2(x) (1LL<<(x))
#define msb(x) (63-__builtin_clzll(x))
#define bitcnt(x) (__builtin_popcountll(x))
#define nl '\n'
#define _ << ' ' <<
#define all(x) (x).begin(), (x).end()
#define rep(i,a,b) for(int i = (int)(a); i < (int)(b); i++)
#define dbg(x) if(1) cout << "?" << #x << " : " << (x) << endl << flush;
#define int long long
// const Int MOD = 1e9+7;
const Int MOD = 998244353;
Int bpow(Int a,Int b){
Int ret = 1;
for(;b; a=a*a%MOD,b/=2) if(b&1) ret = ret*a%MOD;
return ret;
}
Int inv(Int a){return bpow(a,MOD-2);}
void solve(); int TC, ALLTC;
signed main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); cout << fixed << setprecision(7);
// cin >> ALLTC; for(TC=1; TC<=ALLTC; TC++) solve(); return 0;
solve();
}
const int N = 1e5+5;
const int LN = 18;
int n, m, q;
pii edg[N];
V<int> adj[N];
int root;
// regular euler tour
int dep[N], in[N], out[N], tim=1;
void dfs_init(int x=root,int par=0){
in[x] = tim++;
for(int y : adj[x]) if(y!=par){
dep[y] = dep[x]+1;
dfs_init(y, x);
}
out[x] = tim-1;
}
// lca sparse table
// duplicated euler tour
int getMinDepth(int x,int y){
return (dep[x]<dep[y]) ? x : y;
}
struct Stable{
int v[2*N][LN];
void build(){
rep(lg,1,LN) for(int i=0; i+(1<<lg)-1<2*N; i++){
v[i][lg] = getMinDepth(v[i][lg-1], v[i+(1<<(lg-1))][lg-1]);
}
}
int qry(int l,int r){
int lg = __lg(r-l+1);
return getMinDepth(v[l][lg], v[r-(1<<lg)+1][lg]);
}
} stable;
int st[N], stim=1;
int getLca(int x,int y){
if(!(st[x]<st[y])) swap(x,y);
return stable.qry(st[x], st[y]);
}
void dfs_stable(int x=root,int par=0){
st[x] = stim;
stable.v[stim++][0] = x;
for(int y : adj[x]) if(y!=par){
dfs_stable(y, x);
stable.v[stim++][0] = x;
}
}
// fenwick tree, range update, point query
struct Fenw{
// int v[N];
// void reset(){
// rep(i,0,N) v[i] = 0;
// }
// void upd(int l,int r,int val){
// for(l++; l<N; l+=l&-l) v[l]+=val;
// r++;
// for(r++; r<N; r+=r&-r) v[r]-=val;
// }
// int qry(int i){
// int ret = 0;
// for(i++; i; i-=i&-i) ret+=v[i];
// return ret;
// }
#define lc (v+1)
#define rc (v+2*(mid-tl+1))
#define mid (tl+tr)/2
int lz[2*N];
void reset(){
rep(v,0,2*N) lz[v] = 0;
}
void upd(int l,int r,int val,int v=0,int tl=1,int tr=n){
if(r<tl || tr<l) return;
if(l<=tl && tr<=r){
lz[v] += val; return;
}
upd(l,r,val, lc,tl,mid);
upd(l,r,val, rc,mid+1,tr);
}
int qry(int i,int v=0,int tl=1,int tr=n){
if(tl==tr) return lz[v];
if(i<=mid) return lz[v] + qry(i, lc,tl,mid);
else return lz[v] + qry(i, rc,mid+1,tr);
}
int getInPath(int x,int y){
return qry(in[x]) + qry(in[y]) - 2*qry(in[getLca(x,y)]);
}
#undef lc
#undef rc
#undef mid
} counter, silver;
// tax position and cost
int pos[N], c[N];
// queries
int qs[N], qt[N], qx[N], qy[N];
// max #taxes paid by silver
int qans[N];
// range to check
int ql[N], qr[N];
// queries to check
V<int> tochk[N];
void solve(){
cin >> n >> m >> q;
// input edges
rep(e,1,n){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edg[e] = {u,v};
}
root = rng()%n+1;
dfs_init();
assert(tim-1==n);
dfs_stable();
assert(stim-1==2*n-1);
stable.build();
// rep(i,1,n+1) assert(getLca(i,i)==i);
// input taxes
V<int> txord;
rep(i,0,m){
cin >> pos[i] >> c[i];
txord.push_back(i);
// put this tax at child
auto[u,v] = edg[pos[i]];
pos[i] = u ^ v ^ getMinDepth(u,v);
}
sort(all(txord),[&](int i,int j){
return c[i] < c[j];
});
// input queries
rep(i,1,q+1){
cin >> qs[i] >> qt[i] >> qx[i] >> qy[i];
qans[i] = 0;
ql[i] = 0; qr[i] = m-1;
}
// silver.getInPath(1,2);
// return;
// parallel binsearch
while(1){
// rep(loop,0,LN){
// dbg(loop);
bool unsolved = 0;
rep(i,0,m) tochk[i].clear();
rep(i,1,q+1) if(ql[i]<=qr[i]){
tochk[(ql[i]+qr[i])/2].push_back(i);
unsolved = 1;
}
if(!unsolved) break;
counter.reset();
silver.reset();
// insert taxes
rep(i,0,m){
// dbg(i);
// insert tax into euler tour
int idx = txord[i]; // tax ID
int x = pos[idx];
counter.upd(in[x], out[x], 1);
silver.upd(in[x], out[x], c[idx]);
// check queries
for(int j : tochk[i]){
// check whether have enough silver
if(silver.getInPath(qs[j],qt[j]) <= qy[j]){
qans[j] = counter.getInPath(qs[j],qt[j]);
ql[j] = i+1;
}
else{
qr[j] = i-1;
}
}
}
}
counter.reset();
rep(idx,0,m){
int x = pos[idx];
counter.upd(in[x], out[x], 1);
}
// output answer
rep(i,1,q+1){
int ans = qx[i]+qans[i] - counter.getInPath(qs[i],qt[i]);
ans = max(ans, -1LL);
cout << ans << nl;
}
}
