#include <bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define fs first
#define sc second
const int N = 110000;
int n, m, q;
int sz[N], l[N], r[N], idnow = 0, head[N], par[N], dep[N] = {0}, mxson[N], pe[N], eto[N]; // pe是連到我頭上的那條邊的編號
vector <pii> e[N], checkpoint;
vector <pii> route[N];
int cnt[N] = {0};
void dfs_sz (int i, int p) {
par[i] = p, dep[i] = dep[p] + 1, sz[i] = 1;
mxson[i] = -1;
for (auto [j, id] : e[i]) {
if (j == p) continue;
dfs_sz(j, i);
sz[i] += sz[j], mxson[i] = j;
}
for (auto [j, id] : e[i]) if (j != p and sz[j] > sz[mxson[i]]) mxson[i] = j;
}
void build_hld (int i, int p, int hea) {
head[i] = hea, l[i] = ++idnow;
for (auto [j, id] : e[i]) {
if (j == p) pe[l[i]] = id, eto[id] = l[i];
if (j == mxson[i]) build_hld(j, i, hea);
}
for (auto [j, id] : e[i]) if (j != p and j != mxson[i]) build_hld(j, i, j);
r[i] = idnow;
return;}
vector <pii> hld (int a, int b) {
vector <pii> res;
while (head[a] != head[b]) {
if (dep[head[a]] > dep[head[b]]) swap(a, b);
res.push_back({l[head[b]], l[b]});
b = par[head[b]];
}
if (a != b) {
if (dep[a] > dep[b]) swap(a, b);
res.push_back({l[a] + 1, l[b]});
}
return res;}
struct bit {
int n;
long long a[510000];
void init (int nn) {
n = nn;
memset(a, 0, (n + 10) * 8);
}
void update (int i, int x) { for (; i <= n; i += i & -i) a[i] += x; }
long long query (int i) {
if (i > n) i = n;
long long res = 0;
for (; i > 0 ; i -= i & -i) res += a[i];
return res;
}
long long query2 (int l, int r) {return query(r) - query(l - 1);}
} bit;
long long wow (int i) {
long long res = 0;
for (auto p : route[i]) {
res += bit.query2(p.fs, p.sc);
// cout << p.fs << ' ' << p.sc << '\n';
}
return res;
}
int main () {
ios_base ::sync_with_stdio(false);
cin. tie(0);
//build tree
cin >> n >> m >> q;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
e[a] . push_back({b, i});
e[b] . push_back({a, i});
}
//build hld
dfs_sz (1, 1);
build_hld(1, 1, 1);
//input checkpoint
for (int i = 1; i <= m; i++) {
int pos, c;
cin >> pos >> c;
checkpoint . push_back({c, eto[pos]});
}
sort(checkpoint.begin(), checkpoint.end());
//find ans
for (int i = 1; i <= q; i++) {
int s, t, x, y;
cin >> s >> t >> x >> y;
route[i] = hld(s, t);
bit.init(n);
int now = 0;
for (int j = 0; j < m; j++) {
bit.update(checkpoint[j].sc, checkpoint[j].fs);
if (wow(i) > y and wow(i) != now) x--;
now = wow(i);
}
if (x < 0) x = -1;
cout << x << '\n';
}
}
