#include <bits/stdc++.h>
using namespace std;
#define int int64_t
const int Z = 1e5, INF = 1e18;
struct BIT {
int *a, n;
void init(int N) {
a = new int[(n = N) + 1] {};
}
void add(int i, int v) {
for(++i; i <= n; i += i&-i) a[i] += v;
}
int get(int i) {
int v = 0;
for(++i; i >= 1; i -= i&-i) v += a[i];
return v;
}
};
int N, M, Q, p[Z], lca[Z], eL[Z], eR[Z], dfsTimer, ans[Z];
vector<int> g[Z];
vector<array<int, 2>> o;
set<int> s[Z];
array<int, 4> q[Z];
BIT b[2] {};
void dfs0(int u) {
eL[u] = dfsTimer++;
for(int v : g[u]) if(v != p[u]) {
p[v] = u, dfs0(v);
if(size(s[v]) > size(s[u]))
swap(s[u], s[v]);
for(int i : s[v]) {
if(s[u].find(i) == end(s[u]))
s[u].insert(i);
else {
lca[i] = u;
s[u].erase(i);
}
}
}
eR[u] = dfsTimer++;
}
void add(int i, int u, int v) {
b[i].add(eL[u], +v);
b[i].add(eR[u], -v);
}
void modify(int i, int f) {
add(0, o[i][1], o[i][0] * f);
add(1, o[i][1], -f);
}
int calc(int i) {
array<int, 2> val;
for(int j : {0, 1})
val[j] = b[j].get(eL[q[i][0]]) + b[j].get(eL[q[i][1]]) - 2 * b[j].get(eL[lca[i]]);
if(val[0] <= q[i][3])
return q[i][2] - val[1];
else return -INF;
}
void dfs1(int l, int r, vector<int> &qry) {
if(r - l < 2 || empty(qry)) {
for(int i = l; i < r; ++i)
modify(i, +1);
for(int i : qry) ans[i] = calc(i);
if(!l && r == 1) {
modify(0, -1);
for(int i : qry) if(ans[i] == -INF)
ans[i] = calc(i);
modify(0, +1);
}
return;
}
int m = (l + r) / 2;
for(int i = l; i <= m; ++i) modify(i, +1);
vector<int> qv[2];
for(int i : qry)
qv[calc(i) > -INF].push_back(i);
for(int i = l; i <= m; ++i) modify(i, -1);
dfs1(l, m, qv[0]);
dfs1(m, r, qv[1]);
}
signed main() {
cin.tie(0)->sync_with_stdio(0);
cin >> N >> M >> Q;
array<int, 2> edges[N-1], temp[M];
for(auto &[u, v] : edges) {
cin >> u >> v; --u, --v;
g[u].push_back(v);
g[v].push_back(u);
}
for(auto &[i, w] : temp)
cin >> i >> w, --i;
for(int i = 0; i < Q; ++i) {
cin >> q[i][0] >> q[i][1] >> q[i][2] >> q[i][3];
for(int j : {0, 1})
s[--q[i][j]].insert(i);
}
dfs0(0);
for(auto &[i, w] : temp) {
int u = edges[i][p[edges[i][1]] == edges[i][0]];
o.push_back({w, u});
}
for(int i : {0, 1})
b[i].init(2*N);
sort(begin(o), end(o));
for(auto [w, u] : o) add(1, u, 1);
vector<int> qv(Q);
iota(begin(qv), end(qv), 0);
dfs1(0, size(o), qv);
for(int i = 0; i < Q; ++i)
cout << max(ans[i], (int)-1) << '\n';
}
