#include <bits/stdc++.h>
#define ii pair<int, int>
#define fi first
#define se second
using namespace std;
#define int long long
const int N = 1e5 + 5, S = 17;
ii adj[N], p[N], range[N];
vector <int> ke[N], lst[N], gido[N];
struct date{
int u, v, gol, sil;
} t[N];
int n, m, q, d[N], par[N][S], timer, st[N], ed[N], bit[N], cnt[N], ans[N], s[N];
void dfs(int u, int pre = 0) {
d[u] = d[pre] + 1;
par[u][0] = pre;
for(int i = 1; i < S; i++) {
par[u][i] = par[par[u][i - 1]][i - 1];
}
st[u] = ++timer;
for(int v : ke[u]) if(v != par[u][0]) dfs(v, u);
ed[u] = timer;
}
void upd_point(int x, int u, int v) {
while (x <= n) {
bit[x] += u; // coin
cnt[x] += v;
x += (x & (-x));
}
}
void upd_range(int l, int r, int u, int v) {
upd_point(l, u, v);
upd_point(r + 1, -u, -v);
}
void upd_adj(int id) {
int x, coin; x = p[id].se, coin = p[id].fi;
int u, v; u = adj[x].fi, v = adj[x].se;
if(d[u] > d[v]) swap(u, v);
//cout << v << " " << st[v] << " " << ed[v] << " " << coin << "^^\n";
upd_range(st[v], ed[v], coin, 1);
}
int lca(int u, int v) {
if(d[u] > d[v]) swap(u, v);
int dist = d[v] - d[u];
for(int i = S - 1; i >= 0; i--) if((dist >> i) & 1) {
v = par[v][i];
}
if(u == v) return u;
for(int i = S - 1; i >= 0; i--) if(par[u][i] != par[v][i]) {
u = par[u][i], v = par[v][i];
}
return par[u][0];
}
int get_s(int x) {
int ret = 0; x = st[x];
while (x > 0) {
ret += bit[x];
x -= (x & (-x));
}
return ret;
}
int get_g(int x) {
int ret = 0; x = st[x];
while (x > 0) {
ret += cnt[x];
x -= (x & (-x));
}
return ret;
}
int check(int i, int id) {
int u = t[i].u, v = t[i].v, gol = t[i].gol, sil = t[i].sil;
int o = lca(u, v);
int silver = get_s(u) + get_s(v) - 2 * get_s(o);
int gg = get_g(u) + get_g(v) - 2 * get_g(o);
int gold = s[u] + s[v] - 2 * s[o] - gg;
if(silver <= t[i].sil) return gold;
return -1;
}
void dfs2(int u) {
for(int v : ke[u]) if(v != par[u][0]) {
s[v] += s[u];
dfs2(v);
}
}
main () {
// input
cin >> n >> m >> q;
for(int i = 1; i < n; i++) {
int u, v; cin >> u >> v;
adj[i] = make_pair(u, v);
ke[u].push_back(v);
ke[v].push_back(u);
}
for(int i = 1; i <= m; i++) {
cin >> p[i].se >> p[i].fi;
}
for(int i = 1; i <= q; i++) {
cin >> t[i].u >> t[i].v >> t[i].gol >> t[i].sil;
}
// xuli
for(int i = 1; i <= q; i++) ans[i] = 1e9;
sort(p + 1, p + 1 + m);
dfs(1);
int lim = ceil(1.0 * log2(m + 1)) + 1; int mid_f = m / 2;
for(int i = 1; i <= m; i++) {
int x = p[i].se;
int u = adj[x].fi, v = adj[x].se;
if(d[u] > d[v]) swap(u, v);
s[v]++;
}
dfs2(1);
for(int i = 1; i <= q; i++) {
range[i] = make_pair(0, n);
lst[mid_f].push_back(i);
}
// solve
for(int turn = 1; turn <= lim; turn++) {
for(int i = 1; i <= n; i++) bit[i] = cnt[i] = 0;
for(int id = 0; id <= m; id++) {
if(id) upd_adj(id);
for(int i : lst[id]) {
int ok = check(i, id);
if(ok >= 0) {
range[i].fi = id + 1;
ans[i] = min(ans[i], ok);
}
else range[i].se = id - 1;
int mid = (range[i].fi + range[i].se) >> 1;
gido[mid].push_back(i);
}
lst[id].clear();
}
for(int id = 0; id <= m; id++) {
while (gido[id].size()) {
lst[id].push_back(gido[id].back());
gido[id].pop_back();
}
}
}
// output
for(int i = 1; i <= q; i++) {
int res = t[i].gol - ans[i];
cout << (res < 0 ? -1 : res) << "\n";
}
}
