#include<bits/stdc++.h>
#define fi first
#define se second
#define FOR(i, k, n) for(int i = k; i <= n; i++)
#define FOR1(i, k, n) for(int i = k; i >= n; i--)
#define pb push_back
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define vi vector<int>
#define pii pair<int, int>
#define vii vector<pii>
#define ll long long
#define vll vector<ll>
#define pll pair<ll, ll>
#define re return 0
#define mii map<int, int>
#define input "ALONE.inp"
#define output "ALONE.out"
#define rf freopen(input, "r", stdin); freopen(output, "w", stdout)
#define int ll
using namespace std;
const int maxn = 1e5 + 5;
const int mod = 1e9 + 7;
const int base = 998244353;
const int base1 = 31;
const int SZ = 320;
const ll INF = 1e18;
void add(int &a, int b)
{
a += b;
if(a >= mod) a -= mod;
if(a < 0) a += mod;
}
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
return uniform_int_distribution<int>(l, r) (rd);
}
int ver[maxn], n, m, q;
int par[20][maxn], depth[maxn];
vi query[maxn];
pii canh[maxn];
int dem, ans;
struct smt{
ll sum;
int cnt, l, r;
} T[maxn * 25];
vi adj[maxn];
int trueval[maxn];
vi vv;
void DFS(int u)
{
for(auto v : adj[u])
{
if(v == par[0][u])
continue;
par[0][v] = u;
FOR(i, 1, 18)
par[i][v] = par[i - 1][par[i - 1][v]];
depth[v] = depth[u] + 1;
DFS(v);
}
}
int build(int l, int r)
{
int node = ++dem;
if(l == r)
{
T[node].l = T[node].r = T[node].sum = T[node].cnt = 0;
return node;
}
int mid = (l + r) >> 1;
T[node].l = build(l, mid);
T[node].r = build(mid + 1, r);
T[node].sum = T[node].cnt = 0;
return node;
}
int update(int l, int r, int old, int pos)
{
int node = ++dem;
T[node] = T[old];
if(l == r)
{
T[node].cnt++;
T[node].sum += trueval[pos];
return node;
}
int mid = (l + r) >> 1;
if(pos <= mid)
{
T[node].l = update(l, mid, T[old].l, pos);
}
else
{
T[node].r = update(mid + 1, r, T[old].r, pos);
}
T[node].cnt = T[T[node].l].cnt + T[T[node].r].cnt;
T[node].sum = T[T[node].l].sum + T[T[node].r].sum;
return node;
}
void DFS1(int u)
{
for(auto v : adj[u])
{
if(v == par[0][u])
continue;
ver[v] = ver[u];
for(auto x : query[v])
{
ver[v] = update(1, vv.size(), ver[v], x);
}
DFS1(v);
}
}
int LCA(int u, int v)
{
if(depth[u] < depth[v])
swap(u, v);
int h = depth[u] - depth[v];
FOR1(i, 18, 0)
if((h >> i) & 1)
u = par[i][u];
if(u == v)
return u;
FOR(i, 18, 0)
if(par[i][u] != par[i][v])
{
u = par[i][u];
v = par[i][v];
}
return par[0][u];
}
pll tinh(int x, int y, int z)
{
int dem = 0;
ll sum = 0;
dem = T[x].cnt + T[y].cnt - 2 * T[z].cnt;
sum = T[x].sum + T[y].sum - 2 * T[z].sum;
return {dem, sum};
}
int get(int l, int r, int u, int v, int lca, ll val)
{
pll tmp = tinh(u, v, lca);
if(tmp.se <= val)
return tmp.fi;
if(l == r)
{
pll tmp = tinh(u, v, lca);
int dem = tmp.fi;
return min((ll)dem, val / vv[l]);
}
int mid = (l + r) >> 1;
tmp = tinh(T[u].l, T[v].l, T[lca].l);
if(tmp.se <= val)
{
return tmp.fi + get(mid + 1, r, T[u].r, T[v].r, T[lca].r, val - tmp.se);
}
return get(l, mid, T[u].l, T[v].l, T[lca].l, val);
}
signed main()
{
fastio;
cin >> n >> m >> q;
FOR(i, 1, n - 1)
{
int u, v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
canh[i] = {u, v};
}
DFS(1);
FOR(i, 1, m)
{
int id, w;
cin >> id >> w;
vv.pb(w);
if(depth[canh[id].fi] < depth[canh[id].se])
swap(canh[id].fi, canh[id].se);
query[canh[id].fi].pb(w);
}
vv.pb(0);
sort(vv.begin(), vv.end());
vv.erase(unique(vv.begin(), vv.end()), vv.end());
FOR(i, 1, n)
{
FOR(j, 0, (int)query[i].size() - 1)
{
int id = lower_bound(vv.begin(), vv.end(), query[i][j]) - vv.begin();
trueval[id] = query[i][j];
query[i][j] = id;
}
}
ver[1] = build(1, vv.size());
DFS1(1);
while(q--)
{
ll u, v, x, y;
cin >> u >> v >> x >> y;
int lca = LCA(u, v);
x += get(1, vv.size(), ver[u], ver[v], ver[lca], y);
x -= T[ver[u]].cnt - T[ver[lca]].cnt + T[ver[v]].cnt - T[ver[lca]].cnt;
if(x < 0)
cout << "-1\n";
else
cout << x << "\n";
}
re;
}
