#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const int II = 1'000'000'000;
const ll I = 1'000'000'000'000'000'000LL;
const int K = 17;
const int N = 1<<K;
pair<int, int> e[N];
vector<int> ed[N];
int jp[N][K + 1];
int pos[N], pre[N], cnt = 0;
ll drz[2 * N];
pair<ll, ll> il[N];
int v1[N], v2[N], l[N];
int poc[N], kon[N];
ll akt[N];
pair<int, int> que[N];
pair<int, int> dod[N];
ll answer[N];
void Add(int a, int b, ll x)
{
a += N - 1; b += N + 1;
while(a / 2 != b / 2)
{
if(a % 2 == 0) drz[a + 1] += x;
if(b % 2 == 1) drz[b - 1] += x;
a /= 2; b /= 2;
}
}
ll Sum(int v)
{
ll ans = 0LL;
v += N;
while(v > 0)
{
ans += drz[v];
v /= 2;
}
return ans;
}
void DFS(int v)
{
++cnt; pre[v] = cnt; pos[v] = cnt;
for(int i = 1; i <= K; ++i)
jp[v][i] = jp[jp[v][i - 1]][i - 1];
for(int i = 0; i < (int)ed[v].size(); ++i)
{
if(pre[ed[v][i]]) continue;
jp[ed[v][i]][0] = v;
DFS(ed[v][i]);
pos[v] = pos[ed[v][i]];
}
}
int LCA(int a, int b)
{
if(pre[a] > pre[b]) swap(a, b);
for(int i = K; i >= 0; --i)
if(pos[jp[a][i]] < pre[b]) a = jp[a][i];
if(pos[a] < pre[b]) a = jp[a][0];
return a;
}
void Check(int m, int q, bool r)
{
for(int i = 1; i < 2 * N; ++i) drz[i] = 0;
int j = 0;
sort(que + 1, que + 1 + q);
for(int i = 1; i <= q; ++i)
{
while(j < m && dod[j + 1].st <= que[i].st)
{
++j;
if(r)
Add(pre[dod[j].nd], pos[dod[j].nd], dod[j].st);
else
Add(pre[dod[j].nd], pos[dod[j].nd], 1);
}
int a = que[i].nd;
ll cur = Sum(pre[v1[a]]) + Sum(pre[v2[a]]) - 2LL * Sum(pre[l[a]]);
akt[a] = cur;
}
}
void BS(int m, int q)
{
for(int i = 1; i <= q; ++i)
{poc[i] = 0; kon[i] = II;}
for(int xd = 1; xd <= 30; ++xd)
{
for(int i = 1; i <= q; ++i)
que[i] = pair{(poc[i] + kon[i] + 1) / 2, i};
Check(m, q, 1);
for(int i = 1; i <= q; ++i)
{
int s = (poc[i] + kon[i] + 1) / 2;
if(akt[i] > il[i].nd)
kon[i] = s - 1;
else
poc[i] = s;
}
}
}
void DoAns(int m, int q)
{
for(int i = 1; i <= q; ++i)
que[i] = pair{poc[i], i};
Check(m, q, 1);
for(int i = 1; i <= q; ++i)
answer[i] = (il[i].nd - akt[i]) / (ll)(poc[i] + 1);
Check(m, q, 0);
for(int i = 1; i <= q; ++i)
{
answer[i] += akt[i];
que[i] = pair{II + 1, i};
}
Check(m, q, 0);
for(int i = 1; i <= q; ++i)
{
answer[i] = il[i].st - max(0LL, akt[i] - answer[i]);
if(answer[i] < 0LL)
answer[i] = -1LL;
}
}
void Solve()
{
int n, m, q, a, b;
cin >> n >> m >> q;
for(int i = 1; i < n; ++i)
{
cin >> a >> b;
e[i] = pair{a, b};
ed[a].pb(b); ed[b].pb(a);
}
jp[1][0] = 1;
DFS(1);
for(int i = 1; i <= m; ++i)
{
cin >> a >> b;
if(jp[e[a].st][0] == e[a].nd)
a = e[a].st;
else
a = e[a].nd;
dod[i] = pair{b, a};
}
sort(dod + 1, dod + 1 + m);
for(int i = 1; i <= q; ++i)
{
cin >> v1[i] >> v2[i] >> il[i].st >> il[i].nd;
l[i] = LCA(v1[i], v2[i]);
}
BS(m, q);
DoAns(m, q);
for(int i = 1; i <= q; ++i)
cout << answer[i] << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
Solve();
return 0;
}
