#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
ll n,m,q,in[100005],out[100005],dp[21][100005],par[100005],timp,total[100005],init[100005],niv[100005];
vector<pii> g;
vector<int> muchii[100005];
struct date
{
ll p,c;
} v[100005];
bool byc(date a, date b)
{
return a.c<b.c;
}
struct qr
{
ll a,b,gold,silver,best;
} query[100005];
bool isancestor(int a,int b)
{
return in[a]<=in[b]&&out[a]>=out[b];
}
int LCA(int a,int b)
{
if(niv[a]>niv[b])
swap(a,b);
if(isancestor(a,b))
return a;
for(int i=18;i>=0;i--)
if(dp[i][a]!=0&&!isancestor(dp[i][a],b))
a=dp[i][a];
return par[a];
}
void dfs(int nod)
{
timp++;
in[nod]=timp;
dp[0][nod]=par[nod];
for(int i=1;i<=18;i++)
dp[i][nod]=dp[i-1][dp[i-1][nod]];
for(int i:muchii[nod])
if(i!=par[nod])
{
par[i]=nod;
niv[i]=niv[nod]+1;
dfs(i);
}
out[nod]=timp;
}
int getnode(pii p)
{
if(par[p.first]==p.second)
return p.first;
return p.second;
}
struct event
{
ll st,dr,who;
};
bool bymij(event a, event b)
{
ll mija=(a.st+a.dr)/2;
ll mijb=(b.st+b.dr)/2;
return mija<mijb;
}
ll aib[2][100005]; /// 0 -> nr checkpoints, 1 -> suma
int lsb(int x)
{
return x&(-x);
}
void update(ll ind,ll poz,ll val)
{
for(ll i=poz;i<=n;i+=lsb(i))
aib[ind][i]+=val;
}
ll suma(ll ind,ll poz)
{
ll rez=0;
for(ll i=poz;i>=1;i-=lsb(i))
rez+=aib[ind][i];
return rez;
}
vector<event> ev;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>n>>m>>q;
for(int i=1;i<n;i++)
{
ll a,b;
cin>>a>>b;
g.push_back({a,b});
muchii[a].push_back(b);
muchii[b].push_back(a);
}
dfs(1);
for(int i=1;i<=m;i++)
{
ll p,c;
cin>>p>>c;
p=getnode(g[p-1]);
v[i]={p,c};
init[in[p]]++;
init[out[p]+1]--;
}
sort(v+1,v+m+1,byc);
for(int i=1;i<=n;i++)
init[i]+=init[i-1];
for(int i=1;i<=q;i++)
{
ll a,b,x,y;
cin>>a>>b>>x>>y;
ll lca=LCA(a,b);
total[i]=init[in[a]]+init[in[b]]-2*init[lca];
query[i]={a,b,x,y,0};
ev.push_back({1,m,i});
}
while(!ev.empty())
{
sort(ev.begin(),ev.end(),bymij);
for(int i=1;i<=n;i++)
aib[0][i]=aib[1][i]=0;
vector<event> aux;
int poz=1;
for(auto p:ev)
{
ll st=p.st;
ll dr=p.dr;
ll mij=(st+dr)/2;
ll who=p.who;
ll a=query[who].a;
ll b=query[who].b;
ll silver=query[who].silver;
while(poz<=mij)
{
ll nod=v[poz].p;
ll val=v[poz].c;
update(0,in[nod],1);
update(0,out[nod]+1,-1);
update(1,in[nod],val);
update(1,out[nod]+1,-val);
poz++;
}
ll lca=LCA(a,b);
ll s=suma(1,in[a])+suma(1,in[b])-2*suma(1,in[lca]);
if(s<=silver)
{
query[who].best=suma(0,in[a])+suma(0,in[b])-2*suma(0,in[lca]);
st=mij+1;
}
else
dr=mij-1;
if(st<=dr)
aux.push_back({st,dr,who});
}
ev=aux;
}
for(int i=1;i<=q;i++)
{
ll rem=total[i]-query[i].best;
if(rem>query[i].gold)
cout<<-1<<'\n';
else
cout<<query[i].gold-rem<<'\n';
}
return 0;
}
