#include <bits/stdc++.h>
#define Yang8on Nguyen_Dinh_Son
#define sonphamay Nguyen_Dinh_Son
#define aothtday "Two Currencies"
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define ll long long
#define endl '\n'
#define pii pair<int, ll>
#define vi vector<int>
#define pb push_back
#define all(v) v.begin(), v.end()
#define f first
#define s second
#define maxn 100005
#define maxm
#define maxx
#define mod 1000000007
#define base 311
#define ModHas 1000000003ll
#define gb(i, j) ((i >> j) & 1)
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r)
{
return uniform_int_distribution<ll> (l, r)(rng);
}
int n, m, Q;
int h[maxn], cha[maxn][20];
pair<int, int> edge[maxn];
vector<int> o[maxn], store[maxn];
void dfs(int u, int par)
{
for(int v : o[u])
{
if(v == par) continue;
h[v] = h[u] + 1;
cha[v][0] = u;
fi(j, 1, 17)
{
cha[v][j] = cha[ cha[v][j - 1] ][j - 1];
}
dfs(v, u);
}
}
int lca(int u, int v)
{
if(h[u] < h[v]) swap(u, v);
int kc = h[u] - h[v];
fi(i, 0, 17) if( gb(kc, i) ) u = cha[u][i];
if(u == v) return u;
fid(i, 17, 0)
{
if(cha[u][i] != cha[v][i])
{
u = cha[u][i];
v = cha[v][i];
}
}
return cha[u][0];
}
void solve()
{
cin >> n >> m >> Q;
fi(i, 1, n - 1)
{
cin >> edge[i].f >> edge[i].s ;
int u = edge[i].f, v = edge[i].s;
o[u].pb(v);
o[v].pb(u);
}
dfs(1, -1);
fi(i, 1, m)
{
int id;
ll val;
cin >> id >> val;
int u = edge[id].f, v = edge[id].s;
if(h[v] < h[u]) swap(u, v);
store[v].pb(val);
}
fi(i, 1, Q)
{
int u, v, Gold, Silver;
int G = Gold, S = Silver;
cin >> u >> v >> G >> S;
int par = lca(u, v);
priority_queue<ll> q;
while(u != par)
{
for(ll x : store[u])
{
q.push(-x);
}
u = cha[u][0];
}
while(v != par)
{
for(ll x : store[v])
{
q.push(-x);
}
v = cha[v][0];
}
int notok = 0;
while(q.size())
{
ll val = -q.top();
q.pop();
if(S < val)
{
if(G == 0)
{
notok = 1;
break;
}
G --;
}
else S -= val;
}
if(notok) cout << -1 << '\n';
else cout << G << '\n';
}
}
int main()
{
if(fopen(aothtday".inp", "r"))
{
freopen(aothtday".inp","r",stdin);
freopen(aothtday".out","w",stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int nTest = 1;
// cin >> nTest;
while(nTest --)
{
solve();
}
return 0;
}
