#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define ins insert
#define pb push_back
#define foru(i,a,b) for(int i=a;i<=b;i++)
#define ford(i,a,b) for(int i=a;i>=b;i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define int ll
using namespace std;
int n,m,nq;
int cnt,tt[100005],sz[100005],lca[20][100005],dep[100005];
int a[100005],b[100005],G[100005],S[100005],L[100005],R[100005],MID[100005],ANS[100005];
vector<int> adj[100005],tram[100005],query[100005];
vector<pair<int,int>> vv;
pair<int,int> canh[100005];
void dfs(int u,int par)
{
cnt++;
tt[u]=cnt;
sz[u]=1;
for(auto v:adj[u])
{
if(v==par) continue;
dep[v]=dep[u]+1;
dfs(v,u);
lca[0][v]=u;
sz[u]+=sz[v];
}
}
void buildd()
{
for(int i=1;i<=17;i++)
{
for(int j=1;j<=n;j++)
{
lca[i][j]=lca[i-1][lca[i-1][j]];
}
}
}
int getlca(int u,int v)
{
if(dep[u]<dep[v]) swap(u,v);
ford(i,17,0)
{
if(dep[lca[i][u]]>=dep[v])
{
u=lca[i][u];
}
}
if(u==v) return u;
else
{
ford(i,17,0)
{
if(lca[i][u]!=lca[i][v])
{
u=lca[i][u];
v=lca[i][v];
}
}
return lca[0][u];
}
}
struct IT{
int t[400005],lz[400005];
void build(int id,int l,int r)
{
if(l==r)
{
t[id]=0;
lz[id]=0;
return;
}
int mid=(l+r)/2;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
t[id]=0;
lz[id]=0;
}
void push(int id)
{
if(lz[id]==0) return;
t[id*2]+=lz[id];
t[id*2+1]+=lz[id];
lz[id*2]+=lz[id];
lz[id*2+1]+=lz[id];
lz[id]=0;
}
void update(int id,int l,int r,int u,int v,int w)
{
if(r<u||v<l) return;
if(u<=l&&r<=v)
{
t[id]+=w;
lz[id]+=w;
return;
}
push(id);
int mid=(l+r)/2;
update(id*2,l,mid,u,v,w);
update(id*2+1,mid+1,r,u,v,w);
t[id]=t[id*2]+t[id*2+1];
}
int get(int id,int l,int r,int pos)
{
if(pos<l||r<pos) return 0;
if(l==r)
{
return t[id];
}
push(id);
int mid=(l+r)/2;
return get(id*2,l,mid,pos)+get(id*2+1,mid+1,r,pos);
}
};
IT gold,silver;
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
// freopen(".inp","r",stdin);
// freopen(".out","w",stdout);
cin>>n>>m>>nq;
for(int i=1;i<=n-1;i++)
{
int x,y;
cin>>x>>y;
adj[x].pb(y);
adj[y].pb(x);
canh[i]={x,y};
}
for(int i=1;i<=m;i++)
{
int a,b;
cin>>a>>b;
tram[a].pb(b);
vv.pb({b,a});
}
vv.pb({0,0});
sort(vv.begin(),vv.end());
dep[1]=1;
dfs(1,0);
buildd();
for(int i=1;i<=nq;i++)
{
cin>>a[i]>>b[i]>>G[i]>>S[i];
L[i]=0;
R[i]=m;
}
int cc=17;
while(cc--)
{
gold.build(1,1,n);
silver.build(1,1,n);
foru(i,0,m)
{
query[i].clear();
}
foru(i,1,m)
{
int ss=vv[i].fi,id=vv[i].se;
int a=canh[id].fi,b=canh[id].se;
if(dep[a]<dep[b]) swap(a,b);
gold.update(1,1,n,tt[a],tt[a]+sz[a]-1,1);
}
foru(i,1,nq)
{
MID[i]=(L[i]+R[i])/2;
query[MID[i]].pb(i);
}
for(int i=0;i<=m;i++)
{
int ss=vv[i].fi,id=vv[i].se;
int aa=canh[id].fi,bb=canh[id].se;
if(dep[aa]<dep[bb]) swap(aa,bb);
gold.update(1,1,n,tt[aa],tt[aa]+sz[aa]-1,-1);
silver.update(1,1,n,tt[aa],tt[aa]+sz[aa]-1,ss);
// cout<<'?'<<i<<' '<<aa<<' '<<bb<<endl;
for(auto ID:query[i])
{
// cout<<ID<<endl;
int par=getlca(a[ID],b[ID]);
// cout<<'?'<<a[ID]<<' '<<b[ID]<<' '<<par<<endl;
int needgold=gold.get(1,1,n,tt[a[ID]])+gold.get(1,1,n,tt[b[ID]])-2*gold.get(1,1,n,tt[par]);
int needsilver=silver.get(1,1,n,tt[a[ID]])+silver.get(1,1,n,tt[b[ID]])-2*silver.get(1,1,n,tt[par]);
if(needsilver<=S[ID])
{
ANS[ID]=needgold;
// cout<<'?'<<ANS[ID]<<' '<<i<<endl;
L[ID]=MID[ID]+1;
}
else
{
R[ID]=MID[ID]-1;
}
}
}
}
for(int i=1;i<=nq;i++)
{
// cout<<'?'<<i<<' '<<ANS[i]<<'\n';
if(ANS[i]<=G[i])
{
cout<<G[i]-ANS[i]<<'\n';
}
else
{
cout<<-1<<'\n';
}
}
}
/*
em thi cho du co khoc
cung se den ngay phai quen
thien duong van cho ngay em den
*/
