/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e6+100, M = 1e5+10, K = 20, MX = 30;
struct Node{
Node *L, *R;
ll sum;
int num;
Node(){
L = R = nullptr;
sum = num = 0;
}
Node(ll x, int nm){
L = R = nullptr;
sum = x;
num = nm;
}
Node(Node *l, Node *r){
L = l, R = r;
sum = L->sum + R->sum;
num = L->num + R->num;
}
void extend(){
if(L == nullptr) L = new Node();
if(R == nullptr) R = new Node();
}
};
int n, mi, q, s[N], tin[N], tout[N], up[N][K], heavy[N], dep[N], par[N], ESZ[N], ttin[N], toutt[N], timerr = 0;
ll sum[N];
vector<pair<int, int>> g[N], euler;
vector<int> E[N];
vector<Node*> roots;
Node* build(int l, int r){
if(l == r){
return new Node();
}
int m = l+r>>1;
return new Node(build(l, m), build(m+1, r));
}
Node *update(Node *v, int l, int r, int p, ll val){
if(l == r){
return new Node(val, val == 0 ? 0 : 1);
}
int m = l+r>>1;
if(p <= m){
return new Node(update(v->L, l, m, p, val), v->R);
}
return new Node(v->L, update(v->R, m+1, r, p, val));
}
int f(int l, int r, Node *u, Node *v, Node *uu, Node *vv, ll rsilver){
if(l == r){
ll val = v->sum - u->sum + vv->sum - uu->sum;
int nm = v->num - u->num + vv->num - uu->num;
if(val <= rsilver) return nm;
return 0;
}
int m = l+r>>1;
ll val = v->L->sum - u->L->sum + vv->L->sum - uu->L->sum;
int nm = v->L->num - u->L->num + vv->L->num - uu->L->num;
if(val <= rsilver){
v = v->R;
vv = vv->R;
u = u->R;
uu = uu->R;
return nm + f(m+1, r, u, v, uu, vv, rsilver - val);
}
v = v->L;
vv = vv->L;
u = u->L;
uu = uu->L;
return f(l, m, u, v, uu, vv, rsilver);
}
void dfs(int v, int p){
s[v] = 1;
par[v] = p;
dep[v] = dep[p] + 1;
for(auto &U: g[v]){
int u = U.first;
if(u != p){
sum[u] = sum[v] + E[U.second].size();
dfs(u, v);
up[u][0] = v;
}
}
}
void dfs2(int v, int p, int &timer){
// tin[v] = timer - 1;
ttin[v] = timerr++;
// euler.
tin[v] = euler.size() + 1;
for(auto &U: g[v]){
int u = U.first;
if(u != p){
timer += E[U.second].size();
vector<int> V;
for(auto x: E[U.second]){
euler.pb({x, euler.size() + 1});
V.pb(euler.size());
}
dfs2(u, v, timer);
int c = 0;
for(auto x: E[U.second]) euler.pb({x, -V[c++]});
}
}
toutt[v] = timerr++;
}
bool is_parent(int u, int v){
return ttin[u] <= ttin[v] && toutt[v] <= toutt[u];
}
int _lca(int u, int v){
if(is_parent(u, v)) return u;
if(is_parent(v, u)) return v;
for(int j = K-1; j >= 0 ; --j){
if(!is_parent(up[u][j], v)) u = up[u][j];
}
return up[u][0];
}
void solve(){
cin >> n >> mi >> q;
for(int i = 0; i < n - 1; ++i){
int u, v; cin >> u >> v;
g[u].pb({v, i+1});
g[v].pb({u, i+1});
}
for(int i = 0; i < mi; ++i){
int p, c; cin >> p >> c;
E[p].pb(c);
}
dep[1] = 1;
tin[1] = 1;
sum[1] = 0;
dfs(1, 1);
int tm = 1;
dfs2(1, 1, tm);
up[1][0] = 1;
for(int j = 1; j < K; ++j) for(int i = 1; i <= n; ++i) up[i][j] = up[up[i][j - 1]][j - 1];
vector<pair<int, int>> X = euler;
// mi *= 2;
vector<int> pos(mi+1);
sort(all(X));
int c = 0;
for(int i = 0; i < mi*2; ++i) if(X[i].second > 0) pos[X[i].second] = ++c;
roots.pb(build(1, mi));
for(int i = 1; i <= mi*2; ++i){
if(euler[i - 1].second > 0)
roots.pb(update(roots.back(), 1, mi, pos[i], euler[i - 1].first));
else
roots.pb(update(roots.back(), 1, mi, pos[-euler[i - 1].second], 0));
}
for(int i = 0; i < q; ++i){
int s, t; ll x, y; cin >> s >> t >> x >> y;
int lca = _lca(s, t);
int tot_gold = sum[s] + sum[t] - 2*sum[lca];
int rgold = x - (tot_gold - f(1, mi, roots[tin[lca] - 1], roots[tin[s] - 1], roots[tin[lca] - 1], roots[tin[t] - 1], y));
if(rgold < 0) cout << -1 << '\n';
else cout << rgold << '\n';
}
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int tt = 1, aa;
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
while(tt--){
solve();
en;
}
cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
return 0;
}
