#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
#include <random>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
struct ooga{
int a, b, g, s, i;
};
int counter=1;
vector<int> in, out, depth, ft, mx;
vector<vector<int> > graph, twok;
void dfs(int node, int p, int d){
in[node]=counter++;
depth[node]=d;
twok[node][0]=p;
for (int i=1; i<20; ++i)twok[node][i]=twok[twok[node][i-1]][i-1];
for (auto num:graph[node])if (num!=p)dfs(num, node, d+1);
out[node]=counter;
}
int lca(int a, int b){
if (depth[a]<depth[b])swap(a, b);
for (int i=0, k=depth[a]-depth[b]; i<20; ++i)if (k&(1<<i))a=twok[a][i];
if (a==b)return a;
for (int i=19; i>=0; --i)if (twok[a][i]!=twok[b][i])a=twok[a][i], b=twok[b][i];
return twok[a][0];
}
void up(int i, int v){
for (;i<=counter;i+=i&-i)ft[i]+=v;
}
int query(int i){
int res=0;
for (;i;i-=i&-i)res+=ft[i];
return res;
}
bool custom(ooga a, ooga b){
return mx[a.i]<mx[b.i];
}
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m, q, a, b, c, d, p=-1;
cin>>n>>m>>q;
graph.resize(n+1);
in.resize(n+1);
out.resize(n+1);
depth.resize(n+1);
twok.resize(n+1, vector<int>(20));
vector<pii> edges(n), vect(m);
for (int i=1; i<n; ++i){
cin>>a>>b;
graph[a].pb(b);
graph[b].pb(a);
edges[i]=mp(a, b);
}
dfs(1, 1, 0);
ft.resize(counter+1, 0);
for (int i=0; i<m; ++i){
cin>>a>>b;
if (depth[edges[a].fi]>depth[edges[a].se])a=edges[a].fi;
else a=edges[a].se;
vect[i]=mp(b, a);
}
sort(vect.begin(), vect.end());
vector<ooga> quer(q);
vector<int> ans(q), cc(q);
mx.resize(q);
for (int i=0; i<m; ++i)up(in[vect[i].se], 1), up(out[vect[i].se], -1);
for (int i=0; i<q; ++i)cin>>a>>b>>c>>d, quer[i]={a, b, c, d, i}, cc[i]=query(in[a])+query(in[b])-2*query(in[lca(a, b)]);
for (int i=0; i<m; ++i)up(in[vect[i].se], -1), up(out[vect[i].se], 1);
queue<pair<pii, vector<ooga> > > ord;
ord.push(mp(mp(-1, m), quer));
while (ord.size()){
int low=ord.front().fi.fi, high=ord.front().fi.se, mid=(low+high)/2;
vector<ooga> cq=ord.front().se;
ord.pop();
if (low+1>=high){
for (auto a:cq)mx[a.i]=low;
continue;
}
while (p<mid)++p, up(in[vect[p].se], vect[p].fi), up(out[vect[p].se], -vect[p].fi);
while (p>mid)up(in[vect[p].se], -vect[p].fi), up(out[vect[p].se], vect[p].fi), --p;
vector<ooga> left, right;
for (auto c:cq){
if (query(in[c.a])+query(in[c.b])-2*query(in[lca(c.a, c.b)])<=c.s)right.pb(c);
else left.pb(c);
}
if (left.size())ord.push(mp(mp(low, mid), left));
if (right.size())ord.push(mp(mp(mid, high), right));
}
while (p!=-1)up(in[vect[p].se], -vect[p].fi), up(out[vect[p].se], +vect[p].fi), --p;
sort(quer.begin(), quer.end(), custom);
p=0;
for (auto c:quer){
while (p<=mx[c.i])up(in[vect[p].se], 1), up(out[vect[p].se], -1), ++p;
ans[c.i]=max(-1ll, c.g-(cc[c.i]-query(in[c.a])-query(in[c.b])+2*query(in[lca(c.a, c.b)])));
}
for (auto a:ans)cout<<a<<"\n";
}
