#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct checkpoint {
int p;
ll c;
bool operator < (const checkpoint& oth) const {
return c < oth.c;
}
};
const int nmax = 1e5 + 5, lg = 17;
int n, m, q, s[nmax], t[nmax], d[nmax], up[nmax][20], in[nmax], out[nmax], timer, l[nmax], r[nmax], ans[nmax];
checkpoint cp[nmax];
ll x[nmax], y[nmax], bit[nmax], cnt[nmax], total[nmax];
vector <int> g[nmax], bucket[nmax];
pair <int, int> e[nmax];
void dfs(int u) {
in[u] = ++timer;
for (int v : g[u]) {
if (v==up[u][0]) continue;
d[v] = d[u] + 1;
up[v][0] = u;
for (int j=1; j<=lg; j++)
up[v][j] = up[up[v][j-1]][j-1];
dfs(v);
}
out[u] = timer;
}
int lca(int u, int v) {
if (d[u]<d[v]) swap(u, v);
int dif = d[u] - d[v];
for (int j=0; j<=lg; j++)
if (dif >> j & 1) u = up[u][j];
if (u==v) return u;
for (int j=lg; j>=0; j--) {
if (up[u][j]!=up[v][j]) {
u = up[u][j];
v = up[v][j];
}
}
return up[u][0];
}
void update(int i, ll x, ll bit[]) {
while (i<=n) {
bit[i] += x;
i += i & -i;
}
}
ll get(int i, ll bit[]) {
ll sum = 0;
while (i>0) {
sum += bit[i];
i -= i & -i;
}
return sum;
}
void range(int l, int r, ll x, ll bit[]) {
update(l, x, bit);
update(r + 1, -x, bit);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> q;
for (int i=1; i<n; i++) {
int u, v; cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
e[i] = {u, v};
}
for (int i=1; i<=m; i++)
cin >> cp[i].p >> cp[i].c;
for (int i=1; i<=q; i++)
cin >> s[i] >> t[i] >> x[i] >> y[i];
dfs(1);
sort(cp + 1, cp + 1 + m);
for (int i=1; i<=q; i++) {
l[i] = 0;
r[i] = m;
}
bool change = true;
while (change) {
change = false;
int mx = 0;
for (int i=1; i<=q; i++) {
if (l[i]>r[i]) continue;
int mid = (l[i] + r[i]) / 2;
bucket[mid].push_back(i);
mx = max(mx, mid);
change = true;
}
if (!change) break;
for (int mid=0; mid<=m; mid++) {
if (mid>0) {
int u = e[cp[mid].p].first;
if (d[e[cp[mid].p].second]>d[u]) u = e[cp[mid].p].second;
range(in[u], out[u], cp[mid].c, bit);
range(in[u], out[u], 1, cnt);
}
for (int i : bucket[mid]) {
ll sum = get(in[s[i]], bit) + get(in[t[i]], bit) - 2 * get(in[lca(s[i], t[i])], bit);
if (sum<=y[i]) {
total[i] = get(in[s[i]], cnt) + get(in[t[i]], cnt) - 2 * get(in[lca(s[i], t[i])], cnt);
l[i] = mid + 1;
}
else r[i] = mid - 1;
}
}
for (int i=0; i<=m; i++)
bucket[i].clear();
for (int i=1; i<=n; i++)
bit[i] = cnt[i] = 0;
}
for (int i=1; i<=m; i++) {
int u = e[cp[i].p].first;
if (d[e[cp[i].p].second]>d[u]) u = e[cp[i].p].second;
range(in[u], out[u], 1, cnt);
}
for (int i=1; i<=q; i++) {
ll adu = get(in[s[i]], cnt) + get(in[t[i]], cnt) - 2 * get(in[lca(s[i], t[i])], cnt);
if (x[i]>=adu-total[i]) cout << x[i] + total[i] - adu << '\n';
else cout << "-1\n";
}
return 0;
}
