#include <bits/stdc++.h> using namespace std; #define ll long long #define ld long double #define FOR(i,l,r) for(int i = (l), _r = (r); i <= _r; i++) #define FORNG(i,r,l) for(int i = (r), _l = (l); i >= _l; i--) #define REP(i,r) for(int i = 0, _r = (r); i < _r; i++) #define endl '\n' #define fi first #define se second #define pb push_back #define size(v) ((ll)(v).size()) #define all(v) (v).begin(),(v).end() #define MASK(x) (1LL << (x)) #define BIT(x,i) (((x) >> (i)) & 1) const ll MOD = 1e9 + 7, N = 2e5 + 36, LOG = 18; const int INF = 1e9 + 36; ll n,m,q,par[N],high[N]; vector<int> adj[N]; vector<ll> S[N]; pair<int,int> edge[N]; void dfs(int u){ for(int v : adj[u])if(v != par[u]){ high[v] = high[u] + 1; par[v] = u; dfs(v); } } int main(){ //freopen(".INP", "r", stdin); //freopen(".OUT", "w", stdout); ios_base::sync_with_stdio(0);cin.tie(0); cin>>n>>m>>q; FOR(i,1,n-1){ int u,v;cin>>u>>v; edge[i] = {u, v}; adj[u].pb(v); adj[v].pb(u); } dfs(1); FOR(i,1,m){ ll p,c;cin>>p>>c; auto [u, v] = edge[p]; if(high[u] > high[v])S[u].pb(c); else S[v].pb(c); } FOR(i,1,q){ ll s,t,x,y;cin>>s>>t>>x>>y; vector<ll> vec; if(high[s] < high[t])swap(s, t); ll sum = 0; while(high[s] < high[t]){ for(ll v : S[s])vec.pb(v),sum += v; s = par[s]; } while(s != t){ for(ll v : S[s])vec.pb(v),sum += v; for(ll v : S[t])vec.pb(v),sum += v; s = par[s]; t = par[t]; } sort(all(vec), greater<ll>()); for(ll v : vec){ if(sum <= y)break; x--; sum -= v; } if(x < 0)cout<<-1<<endl; else cout<<x<<endl; } }