#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(),a.end()
#define rep(a,b) for(int a = 0;a<b;a++)
const int inf = 1e9;
const ll infl = 1e18;
int d[100000];
int cpr = 0;
int pr[100000];
int rpr[100000];
int mpr[100000];
bool vis[100000];
int jp[100000][20];
vector<int> gr[100000];
void dfs(int v,int cd)
{
d[v] = cd;
vis[v] = true;
rpr[cpr] = v;
pr[v] = cpr;
cpr++;
for(int i : gr[v])
{
if(!vis[i])
{
jp[i][0] = v;
dfs(i,cd+1);
}
}
mpr[v] = cpr;
}
int lca(int a,int b)
{
if(d[a] < d[b]) swap(a,b);
for(int i = 19;i>=0;i--)
{
if(d[a] - (1<<i) >= d[b])
{
a = jp[a][i];
}
}
for(int i = 19;i>=0;i--)
{
if(jp[a][i] != jp[b][i])
{
a = jp[a][i];
b = jp[b][i];
}
}
if(a==b)return a;
return jp[a][0];
}
int n,m,q;
pair<int,int> tr[200000];
void add(int l,int r,int v,int v2)
{
//cerr<<l<<" "<<r<<" "<<v2<<" CAMERAMAN"<<"\n";
l+=n;r+=n;
tr[l].st += v;
tr[l].nd += v2;
if(l != r)
{
tr[r].st += v;
tr[r].nd += v2;
}
while(l/2 != r/2)
{
if(l%2==0)
{
tr[l+1].st+=v;
tr[l+1].nd+=v2;
}
if(r%2==1)
{
tr[r-1].st+=v;
tr[r-1].nd+=v2;
}
l/=2;r/=2;
}
}
pair<ll,int> check(int p)
{
p = pr[p];
p += n;
pair<ll,int> ans = {0,0};
while(p > 0)
{
ans.st += tr[p].st;
ans.nd += tr[p].nd;
p/=2;
}
return ans;
}
void add2(int p,int c)
{
add(pr[p],mpr[p]-1,c,-1);
}
vector<pair<int,int>> ch;
void my_clear()
{
rep(i,n*2)
{
tr[i] = {0,0};
}
rep(i,m)
{
//cerr<<ch[i].st<<" "<<ch[i].nd<<" "<<rpr[ch[i].nd]<<" "<<mpr[rpr[ch[i].nd]]<<" aaa\n";
add(ch[i].nd,mpr[rpr[ch[i].nd]]-1,0,1);
}
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
//cerr.tie(0);
cin>>n>>m>>q;
ch.resize(m);
vector<pair<int,int>> kr(n-1);
rep(i,n-1)
{
int a,b;
cin>>a>>b;
a--;b--;
gr[a].pb(b);
gr[b].pb(a);
kr[i] = {a,b};
}
dfs(0,0);
jp[0][0] = 0;
for(int i = 1;i<20;i++)
{
rep(j,n)
{
jp[j][i] = jp[jp[j][i-1]][i-1];
}
}
rep(i,m)
{
int p,c;
cin>>p>>c;
p--;
ch[i] = {c,max(pr[kr[p].st],pr[kr[p].nd])};
////cerr<<ch[i].nd<<"\n";
}
// //cerr<<"\n";
// return 0;
sort(all(ch));
vector<array<ll,6>> que(q);
vector<pair<ll,int>> cans(q);
rep(i,q)
{
cin>>que[i][0]>>que[i][1]>>que[i][2]>>que[i][3];
que[i][0]--;que[i][1]--;
que[i][4] = 0;
que[i][5] = inf+1;
}
vector<pair<ll,int>> rbs(q);
for(int i = 0;i<31;i++)
{
//cerr<<"\n";
my_clear();
rbs.clear();
rbs.resize(q);
rep(j,q)
{
rbs[j] = {(que[j][4]+que[j][5])/2,j};
}
sort(all(rbs));
int r = 0;
rep(j,q)
{
while(r < m && ch[r].st <= rbs[j].st)
{
add2(rpr[ch[r].nd],ch[r].st);
//cerr<<ch[r].st<<" "<<ch[r].nd<<" "<<rpr[ch[r].nd]<<" TOILET\n";
r++;
}
int cu = rbs[j].nd;
if(que[cu][4] + 1 >= que[cu][5]) continue;
pair<ll,int> cc;
cc.st = check(que[cu][0]).st + check(que[cu][1]).st - check(lca(que[cu][0],que[cu][1])).st * 2;
//cerr<< check(que[cu][0]).nd<<" "<<check(que[cu][1]).nd<<" "<<check(lca(que[cu][0],que[cu][1])).nd<<" "<<que[cu][1]<<" SKIBIDI\n";
cc.nd = check(que[cu][0]).nd + check(que[cu][1]).nd - check(lca(que[cu][0],que[cu][1])).nd * 2;
//cerr<<j<<" "<<rbs[j].st<<" "<<rbs[j].nd<<"\n";
if(cc.st >= que[cu][3])
{
//cerr<<rbs[j].st<<" "<<rbs[j].nd<<"\n";
cans[cu] = {cc.st,cc.nd};
que[cu][5] = rbs[j].st;
}
else
{
que[cu][4] = rbs[j].st;
}
}
}
vector<int> tans(q);
rep(i,q)
{
//cerr<<cans[i].nd<<" "<<que[i][5]<<" "<<cans[i].st<<" "<<que[i][3]<<"\n";
tans[i] = que[i][2]-cans[i].nd - (que[i][5] - 1 + cans[i].st - que[i][3])/que[i][5];
if(tans[i] < 0)
{
cout<<-1<<"\n";
}
else
{
cout<<tans[i]<<"\n";
}
}
}
