#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 998244353
const int N = 100010, lg = 20;
ll n, m, k, x[N], y[N], a[N], ccol[N], ts[4 * N], tc[4 * N], tl[4 * N], trt[4 * N], roots[N], cc = 0, p[N][lg], h[N];
vector<ll> g[N], g2[N];
vector<vector<ll>> col;
int update(int u, int id, int l = 0, int r = m)
{
if (id < l || r <= id)
return u;
cc++;
ll xx = cc;
ts[xx] = ts[u];
tc[xx] = tc[u];
tl[xx] = tl[u];
trt[xx] = trt[u];
ts[xx] += col[id][0];
tc[xx] += 1;
if (r - l == 1)
return xx;
ll m = (l + r) / 2;
tl[xx] = update(tl[xx], id, l, m);
trt[xx] = update(trt[xx], id, m, r);
return xx;
}
int query(int r1, int r2, int r3, ll s, int l = 0, int r = m)
{
if (tc[r2] + tc[r3] - 2 * tc[r1] <= 1)
{
return (s < ts[r2] + ts[r3] - 2 * ts[r1]) ? 1 : 0;
}
ll m = (l + r) / 2;
if (ts[tl[r2]] + ts[tl[r3]] - 2 * ts[tl[r1]] > s)
{
return query(tl[r1], tl[r2], tl[r3], s, l, m) + tc[trt[r2]] + tc[trt[r3]] - 2 * tc[trt[r1]];
}
else
{
return query(trt[r1], trt[r2], trt[r3], s - (ts[tl[r2]] + ts[tl[r3]] - 2 * ts[tl[r1]]), m, r);
}
}
void dfs(int u, int par)
{
p[u][0] = par;
roots[u] = roots[par];
for (auto i : g2[u])
{
if (x[a[i]] == par or y[a[i]] == par)
{
roots[u] = update(roots[u], ccol[i]);
}
}
for (auto i : g[u])
{
if (i != par)
{
h[i] = h[u] + 1;
dfs(i, u);
}
}
}
int lca(int x1, int y1)
{
if (h[x1] > h[y1])
swap(x1, y1);
ll d = h[y1] - h[x1];
for (int i = 0; i < lg; i++)
{
if ((1ll << i) & d)
y1 = p[y1][i];
}
if (x1 == y1)
return x1;
for (int i = lg - 1; i >= 0; i--)
{
if (p[x1][i] != p[y1][i])
{
x1 = p[x1][i];
y1 = p[y1][i];
}
}
return p[x1][0];
}
void solve()
{
cin >> n >> m >> k;
for (int i = 1; i < n; i++)
{
cin >> x[i] >> y[i];
g[x[i]].push_back(y[i]);
g[y[i]].push_back(x[i]);
}
for (int i = 1; i <= m; i++)
{
cin >> a[i] >> ccol[i];
col.push_back({ccol[i], i});
g2[x[a[i]]].push_back(i);
g2[y[a[i]]].push_back(i);
}
sort(col.begin(), col.end());
for (int i = 0; i < m; i++)
{
ccol[col[i][1]] = i;
}
roots[0] = 0;
dfs(1, 0);
for (int j = 1; j < lg; j++)
{
for (int i = 1; i <= n; i++)
{
p[i][j] = p[p[i][j - 1]][j - 1];
}
}
for (int i = 0; i < k; i++)
{
ll s, e, gl, sl;
cin >> s >> e >> gl >> sl;
ll z = lca(s, e);
cout << max(gl - query(roots[z], roots[s], roots[e], sl), -1ll) << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int tests = 1;
// cin >> tests;
for (int i = 1; i <= tests; i++)
{
// cout << "Case #" << i << ": ";
solve();
}
return 0;
}
