#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<long long, long long>
#define pb push_back
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define int long long
const ll N = 1e5 + 100;
const ll inf = 1e18;
const ll block = 350;
ll n,m,q,timer=0;
vector<ll>adj[N];
ll tin[N], tout[N], cur[N], up[N][20], d[N], ps[N], ans[N];
pll e[N];
vector<pll>cost;
struct queries{ll u,v,x,y;} h[N];
struct value{ll ans,f,s;} res[N];
struct ccjv{ll s,t,x,y,l,r,idx;};
vector<ccjv>g;
map<ll,vector<ll>>mp, upd;
struct Fen{
vector<ll>bit1, bit2;
void init(ll _n){
bit1.clear(); bit2.clear();
bit1.resize(_n + 10), bit2.resize(_n + 10);
};
void updatePoint(vector<ll>& b, int u, ll v) {
int idx = u;
while (idx <= n) {
b[idx] = (b[idx] + v);
idx += (idx & (-idx));
}
}
void updateRange(int l, int r, ll v) {
updatePoint(bit1, l, ((n - l + 1) * v));
updatePoint(bit1, r + 1, (-(n - r) * v));
updatePoint(bit2, l, v);
updatePoint(bit2, r + 1, -v);
}
ll getSum(vector<ll>& b, ll u) {
ll idx = u, ans = 0;
while (idx > 0) {
ans = (ans + b[idx]);
idx -= (idx & (-idx));
}
return ans;
}
ll prefixSum(ll u) {
ll x = (getSum(bit1, u) - (getSum(bit2, u) * (n - u)));
return x;
}
ll rangeSum(int l, int r) {
ll x = (prefixSum(r) - prefixSum(l - 1));
return x;
}
} ft, cnt;
void pre_dfs(ll u, ll par){
tin[u] = ++timer;
for(auto v : adj[u]){
if(v == par) continue;
up[v][0] = u;
for(int i = 1; i <= 19;i++) up[v][i] = up[up[v][i-1]][i-1];
d[v] = d[u] + 1;
pre_dfs(v, u);
}
tout[u] = timer;
}
void re_dfs(ll u, ll par){
for(auto v : adj[u]){
if(v == par) continue;
ps[v] += ps[u];
re_dfs(v, u);
}
}
ll lca(ll u, ll v){
if(d[u] != d[v]){
if(d[u] < d[v]) swap(u, v);
ll k = d[u] - d[v];
for(int i = 19; i >= 0;i--) if(k & (1 << i)) u = up[u][i];
}
if(u == v) return u;
for(int i = 19; i >= 0;i--) if(up[u][i] != up[v][i]) u = up[u][i], v = up[v][i];
return up[u][0];
}
void calc(){
if(!g.size()) return;
sort(all(g), [&](const ccjv &a, const ccjv&b){
return (a.l + a.r) / 2 < (b.l + b.r) / 2;
});
ll j = 0;
ft.init(n); cnt.init(n);
vector<ccjv>cur;
for(auto tmp : g){
ll u = tmp.s, v = tmp.t, x = tmp.x, y = tmp.y, l = tmp.l, r = tmp.r, idx = tmp.idx, p = lca(u, v), mid = (l + r) / 2;
while(j < cost.size() && cost[j].F <= mid){
ll i = cost[j].S;
ft.updateRange(tin[e[i].F], tout[e[i].F], cost[j].F);
cnt.updateRange(tin[e[i].F], tout[e[i].F], 1);
j++;
}
ll w = ft.rangeSum(tin[u], tin[u]) + ft.rangeSum(tin[v], tin[v]) - 2 * ft.rangeSum(tin[p], tin[p]);
if(w <= y){
res[idx] = {mid, cnt.rangeSum(tin[u], tin[u]) + cnt.rangeSum(tin[v], tin[v]) - 2 * cnt.rangeSum(tin[p], tin[p]), w};
if(mid + 1 <= r) cur.pb({u,v,x,y,mid+1,r,idx});
}
else if(l + 1 <= mid) cur.pb({u,v,x,y,l,mid-1,idx});
}
swap(cur, g);
}
void to_thic_cau(){
cin >> n >> m >> q;
for(int i = 1; i <= n - 1;i++){
ll u,v; cin >> u >> v;
e[i] = {u, v};
adj[u].pb(v); adj[v].pb(u);
}
pre_dfs(1, 0);
for(int i = 1; i <= m;i++){
ll idx,c; cin >> idx >> c;
if(up[e[idx].F][0] != e[idx].S) swap(e[idx].F, e[idx].S);
ps[e[idx].F]++;
cost.pb({c, idx});
upd[c].pb(idx);
}
re_dfs(1, 0);
sort(all(cost));
for(int i = 1; i <= q;i++){
ll s,t,x,y; cin >> s >> t >> x >> y;
g.pb({s,t,x,y,0,(ll)1e9,i});
h[i] = {s,t,x,y};
}
for(int i = 1; i <= q;i++) res[i].ans = -1;
for(int i = 1; i <= 30;i++) calc();
vector<ll>order;
for(int i = 1; i <= q;i++){
if(res[i].ans == -1) continue;
order.pb(res[i].ans + 1);
mp[res[i].ans + 1].pb(i);
}
//for(int i = 1; i <= n;i++) cout << res[i].s << ' ';
//cout << '\n';
sort(all(order)); order.erase(unique(all(order)), order.end());
cnt.init(n);
for(auto tmp : order){
for(auto i : upd[tmp]) cnt.updateRange(tin[e[i].F], tout[e[i].F], 1);
for(auto i : mp[tmp]){
ll u = h[i].u, v = h[i].v, x = h[i].x, y = h[i].y;
ll p = lca(u, v);
ll rem = cnt.rangeSum(tin[u], tin[u]) + cnt.rangeSum(tin[v], tin[v]) - 2 * cnt.rangeSum(tin[p], tin[p]);
rem = min(rem, (y - res[i].s) / tmp);
ll freq = res[i].f + rem;
ll len = ps[u] + ps[v] - 2 * ps[lca(u, v)];
len -= freq;
if(len > x) ans[i] = -1;
else ans[i] = x - len;
}
for(auto i : upd[tmp]) cnt.updateRange(tin[e[i].F], tout[e[i].F], -1);
}
for(int i = 1; i <= q;i++) cout << ans[i] << '\n';
cout << '\n';
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
//cin >> tc;
while(tc--) to_thic_cau();
}
