#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int n, m, q;
vector<pair<int, int> > tab[100005];
vector<pair<int, int> > adds;
vector<int> mids[100005];
struct query
{
int l;
int r;
int mid;
int lca;
int a;
int b;
int gold;
int wyn;
long long silver;
int coinsatloss = 0;
};
vector<query> queries;
int jp[100005][21];
int checked[100006];
int timee = 1;
int preorder[100005];
int postorder[100005];
pair<long long, int> tree[500005];
int base;
int vfe[100005];
void dfs(int p, int parent)
{
preorder[p] = timee;
timee++;
for(int i = 0; i < tab[p].size(); i++)
{
if(tab[p][i].first != parent)
{
vfe[tab[p][i].second] = tab[p][i].first;
checked[tab[p][i].first] = checked[p] + 1;
jp[tab[p][i].first][0] = p;
for(int o = 1; (1 << o) <= checked[tab[p][i].first]; o++)
{
jp[tab[p][i].first][o] = jp[ jp[tab[p][i].first] [o-1] ][o - 1];
}
dfs(tab[p][i].first, p);
}
}
postorder[p] = timee;
timee++;
}
void upd(int a, int val, int add)
{
a += base;
tree[a].first += val;
tree[a].second += add;
a/=2;
while(a != 0)
{
tree[a].first = tree[a*2].first + tree[a*2+1].first;
tree[a].second = tree[a*2].second + tree[a*2+1].second;
a/=2;
}
}
long long treequery(int a, int b)
{
a += base - 1;
b += base + 1;
long long res = 0 ;
while(a/2 != b/2)
{
if(a % 2 == 0)
{
res += tree[a+1].first;
}
if(b % 2 == 1)
{
res += tree[b-1].first;
}
a/=2;
b/=2;
}
return res;
}
int treequeryamount(int a, int b)
{
a += base - 1;
b += base + 1;
int res = 0 ;
while(a/2 != b/2)
{
if(a % 2 == 0)
{
res += tree[a+1].second;
}
if(b % 2 == 1)
{
res += tree[b-1].second;
}
a/=2;
b/=2;
}
return res;
}
int LCA(int a, int b)
{
if(checked[b] > checked[a])
{
swap(a, b);
}
for(int i = 20; i >= 0; i--)
{
if(checked[a] - checked[b] >= (1 << i))
{
a = jp[a][i];
}
}
if(a == b)
{
return a;
}
for(int i = 20; i >= 0; i--)
{
if(jp[a][i] != jp[b][i])
{
a = jp[a][i];
b = jp[b][i];
}
}
return jp[a][0];
}
void superbinsearch()
{
int leftt = q;
while (leftt > 0)
{
for(int i = 0; i < m; i++)
{
upd(preorder[vfe[adds[i].second]], adds[i].first, 1);
upd(postorder[vfe[adds[i].second]], -adds[i].first, -1);
for(int qnum : mids[i])
{
long long wyn = 0;
int a = queries[qnum].a;
int b = queries[qnum].b;
if(checked[a] < checked[b])
{
swap(a, b);
}
wyn += treequery(preorder[queries[qnum].lca], preorder[a]);
wyn -= tree[preorder[queries[qnum].lca] + base].first;
if(b != queries[qnum].lca)
{
wyn += treequery(preorder[queries[qnum].lca], preorder[b]);
wyn -= tree[preorder[queries[qnum].lca] + base].first;
}
//cout << "mid" << i << " qnum" << qnum << " wyn" << wyn << endl;
if(wyn > queries[qnum].silver)
{
queries[qnum].r = queries[qnum].mid - 1;
}
else
{
queries[qnum].l = queries[qnum].mid + 1;
}
if(queries[qnum].r < queries[qnum].l)
{
leftt--;
queries[qnum].wyn = queries[qnum].r;
}
else
{
queries[qnum].mid = (queries[qnum].l + queries[qnum].r)/2;
mids[queries[qnum].mid].push_back(qnum);
}
}
mids[i].clear();
}
for(int i = 0; i < 2*n + base + 1000; i++)
{
tree[i].first = 0;
tree[i].second = 0;
}
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> q;
base = 2 * n;
for(int i = 1; i <= n-1; i++)
{
int a, b;
cin >> a >> b;
tab[a].push_back({b, i});
tab[b].push_back({a, i});
}
dfs(1, 1);
for(int i = 0; i < m; i++)
{
int a, b;
cin >> a >> b;
adds.push_back({b, a});
}
for(int i = 0; i < q; i++)
{
int a, b, c;
long long d;
cin >> a >> b >> c >> d;
query que;
que.a = a;
que.b = b;
que.gold = c;
que.silver = d;
que.l = 0;
que.r = m-1;
que.mid = (m-1)/2;
que.lca = LCA(a, b);
mids[que.mid].push_back(i);
queries.push_back(que);
}
sort(adds.begin(), adds.end());
superbinsearch();
for(int i = 0; i < q; i++)
{
mids[queries[i].wyn].push_back(i);
}
for(int i = 0; i < m; i++)
{
upd(preorder[vfe[adds[i].second]], adds[i].first, 1);
upd(postorder[vfe[adds[i].second]], -adds[i].first, -1);
for(int qnum : mids[i])
{
int wyn = 0;
int a = queries[qnum].a;
int b = queries[qnum].b;
if(checked[a] < checked[b])
{
swap(a, b);
}
wyn += treequeryamount(preorder[queries[qnum].lca], preorder[a]);
wyn -= tree[preorder[queries[qnum].lca] + base].second;
if(b != queries[qnum].lca)
{
wyn += treequeryamount(preorder[queries[qnum].lca], preorder[b]);
wyn -= tree[preorder[queries[qnum].lca] + base].second;
}
queries[qnum].coinsatloss = wyn;
}
mids[i].clear();
}
for(int i = 0; i < q; i++)
{
int wyn = 0;
int a = queries[i].a;
int b = queries[i].b;
if(checked[a] < checked[b])
{
swap(a, b);
}
wyn += treequeryamount(preorder[queries[i].lca], preorder[a]);
wyn -= tree[preorder[queries[i].lca] + base].second;
if(b != queries[i].lca)
{
wyn += treequeryamount(preorder[queries[i].lca], preorder[b]);
wyn -= tree[preorder[queries[i].lca] + base].second;
}
// cout << "wyn " << wyn << " buyable " << queries[i].coinsatloss << endl;
cout << max(-1, queries[i].gold - wyn + queries[i].coinsatloss) << endl;
}
}
