#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
ll M = 1e5 + 10;
ll base = 1<<18;
ll maxlog = 17;
ll nxt = 0;
vector<ll> Tree(2*base,0);
vector<vector<ll>> g(M), j(M, vector<ll>(maxlog+1));
vector<ll> dep(M), pre(M), post(M);
vector<pair<ll, ll>> edges(M);
void update(ll a, ll b, ll val) {
a+=base-1;
b+=base+1;
while(a/2 != b/2) {
if(a%2==0) Tree[a+1] += val;
if(b%2==1) Tree[b-1] += val;
a/=2; b/=2;
}
}
ll query(ll x) {
x+=base;
ll ans = 0;
while(x>0) {
ans += Tree[x];
x/=2;
}
return ans;
}
void dfs(ll v, ll p) {
pre[v] = ++nxt;
dep[v] = dep[p] + 1;
j[v][0] = p;
for(ll i=1; i<=maxlog; ++i) j[v][i] = j[j[v][i-1]][i-1];
for(auto u : g[v]) if(u!=p) dfs(u,v);
post[v] = ++nxt;
}
ll lca(ll a, ll b) {
if(dep[b] > dep[a]) swap(a,b);
for(ll i=maxlog; i>=0; --i) {
if(dep[j[a][i]] >= dep[b]) a = j[a][i];
}
if(a==b) return a;
for(ll i=maxlog; i>=0; --i) {
if(j[a][i] != j[b][i]) {
a=j[a][i];
b=j[b][i];
}
}
return j[a][0];
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
ll n, m, q;
cin >> n >> m >> q;
for(ll i=1; i<n; ++i) {
ll a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
edges[i] = {a,b};
}
dfs(1, 0);
for(ll i=1; i<n; ++i) {
auto[a,b] = edges[i];
if(dep[a] > dep[b]) swap(edges[i].first, edges[i].second);
}
vector<pair<ll, ll>> pays;
for(ll i=0; i<m; ++i) {
ll p,c;
cin >> p >> c;
pays.push_back({c, edges[p].second});
}
sort(pays.begin(), pays.end());
vector<ll> start(q,0), koniec(q,m);
vector<ll> s(q), t(q), l(q), gold(q), silver(q);
for(ll i=0; i<q; ++i) {
cin >> s[i] >> t[i] >> gold[i] >> silver[i];
l[i] = lca(s[i], t[i]);
}
auto get_sum = [&](ll type) {
return query(pre[s[type]]) + query(pre[t[type]]) - 2*query(pre[l[type]]);
};
ll ile = 0;
while(ile < q) {
vector<pair<ll, ll>> sweep;
vector<ll> mid(q);
for(ll i=0; i<q; ++i) {
mid[i] = (start[i] + koniec[i] + 1)/2;
sweep.push_back({mid[i], i});
}
for(ll i=0; i<m; ++i) {
sweep.push_back({i, q});
}
sort(sweep.begin(), sweep.end());
Tree.assign(2*base,0);
for(auto[czas, type] : sweep) {
if(type==q) {
auto[c, x] = pays[czas];
update(pre[x], post[x], c);
} else {
ll suma = get_sum(type);
if(suma <= silver[type]) start[type] = mid[type];
else koniec[type] = mid[type]-1;
}
}
ile = 0;
for(ll i=0; i<q; ++i) {
if(start[i] >= koniec[i]) ile++;
}
}
vector<ll> saved(q);
Tree.assign(2*base,0);
vector<pair<ll, ll>> sweep;
vector<ll> mid(q);
for(ll i=0; i<q; ++i) {
sweep.push_back({start[i], i});
}
for(ll i=0; i<m; ++i) {
sweep.push_back({i, q});
}
sort(sweep.begin(), sweep.end());
Tree.assign(2*base,0);
for(auto[czas, type] : sweep) {
if(type==q) {
auto[c, x] = pays[czas];
update(pre[x], post[x], 1);
} else {
saved[type] = get_sum(type);
}
}
for(ll i=0; i<q; ++i) {
int uzyte = get_sum(i) - saved[i];
cout << max(-1LL, gold[i] - uzyte) << "\n";
}
return 0;
}
