#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mn = 1e5 + 5;
ll n, m, q, x, y, e1[mn], e2[mn], t = 0, in[mn], out[mn], l[mn], r[mn], jump[mn][21], bit[mn], a[mn], ans[mn], b[mn], c[mn], d[mn], mid[mn], lc[mn];
pair<ll, ll> p[mn];
vector<ll> v[mn], que[mn];
void build(){
for(int i = 0; i <= 2 * n; ++i) bit[i] = 0;
return;
}
void update(ll i, ll val){
for(; i <= 2 * n; i = i | (i + 1)) bit[i] += val;
return;
}
ll get(ll r){
ll ret = 0;
for(; r >= 0; r = (r & (r + 1)) - 1) ret += bit[r];
return ret;
}
void dfs(ll i, ll parent){
in[i] = ++t;
jump[i][0] = parent;
for(int j = 1; j <= 20; ++j) jump[i][j] = jump[jump[i][j - 1]][j - 1];
for(auto j : v[i]){
if(parent == j) continue;
dfs(j, i);
}
out[i] = ++t;
return;
}
bool anc(ll u, ll v){
return in[u] <= in[v] && out[v] <= out[u];
}
ll lca(ll u, ll v){
if(anc(u, v)) return u;
if(anc(v, u)) return v;
for(int i = 20; i >= 0; --i){
if(!anc(jump[u][i], v)) u = jump[u][i];
}
return jump[u][0];
}
void solve(){
cin >> n >> m >> q;
for(int i = 1; i < n; ++i) cin >> e1[i] >> e2[i], v[e1[i]].push_back(e2[i]), v[e2[i]].push_back(e1[i]);
for(int i = 1; i <= m; ++i) cin >> p[i].second >> p[i].first;
sort(p + 1, p + m + 1);
dfs(1, 1);
for(int i = 1; i <= q; ++i) cin >> a[i] >> b[i] >> c[i] >> d[i], l[i] = 1, r[i] = m, lc[i] = lca(a[i], b[i]);
for(int i = 1; i < n; ++i){
if(jump[e1[i]][0] == e2[i]) swap(e1[i], e2[i]);
}
while(true){
ll ok = q;
for(int i = 1; i <= q; ++i){
if(l[i] > r[i]) --ok;
else mid[i] = (l[i] + r[i]) / 2, que[mid[i]].push_back(i);
}
if(!ok) break;
build();
for(int i = 1; i <= m; ++i){
update(in[e2[p[i].second]], p[i].first);
update(out[e2[p[i].second]], 0 - p[i].first);
for(ll j : que[i]){
ll s = get(in[a[j]]) + get(in[b[j]]) - 2 * get(in[lc[j]]);
if(s <= d[j]) l[j] = i + 1;
else r[j] = i - 1;
}
que[i].clear();
}
}
// reverse(p + 1, p + m + 1);
// for(int i = 1; i <= m; ++i) cout << p[i].second << " " << p[i].first << "\n";
for(int i = 1; i <= q; ++i){
que[r[i]].push_back(i);
// cout << l[i] << " "<< r[i] << "\n";
}
build();
// for(int i = m; i >= 1; --i) update(in[e2[p[i].second]], 1), update(out[e2[p[i].second]], -1);
for(int i = m; i >= 0; --i){
for(ll j : que[i]){
ll s = get(in[a[j]]) + get(in[b[j]]) - 2 * get(in[lc[j]]);
// cout << i << " " << j << " " << get(in[a[j]]) << " " << get(in[b[j]]) << " " << get(in[lc[j]]) << " " << c[j] << "\n";
if(s <= c[j]) ans[j] = c[j] - s;
else ans[j] = -1;
}
if(i > 0)update(in[e2[p[i].second]], 1), update(out[e2[p[i].second]], -1);
// , cout << i << " "<< e2[p[i].second] << "\n";
}
for(int i = 1; i <= q; ++i) cout << ans[i] << "\n";
return;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
if(fopen(".INP", "r")) {
freopen(".INP", "r", stdin);
freopen(".OUT", "w", stdout);
}
int testCase = 1;
//cin >> testCase;
while(testCase--) solve();
}
