#include <bits/stdc++.h>
using namespace std;
int const MAX=1e5+5;
int const SQRT=316;
int const INF=1e9;
int n,m,q;
vector<int>in[MAX];
struct path{
int nod,cnt;
};
vector<path>precalc[MAX];
void read(){
cin>>n>>m>>q;
int i;
for(i=1;i<=m;++i){
int s,e;
cin>>s>>e;
in[e].push_back(s);
}
}
bool folosit[MAX];
void merge_(vector<path>&dest,vector<path>v1,vector<path>v2){
dest.clear();
int id1=0,id2=0;
while(id1<(int)v1.size() && id2<(int)v2.size()){
if(v1[id1].cnt>=v2[id2].cnt){
if(!folosit[v1[id1].nod]){
folosit[v1[id1].nod]=1;
dest.push_back(v1[id1]);
}
++id1;
}
else{
if(!folosit[v2[id2].nod]){
folosit[v2[id2].nod]=1;
dest.push_back(v2[id2]);
}
++id2;
}
}
while(id1<(int)v1.size()){
if(!folosit[v1[id1].nod]){
folosit[v1[id1].nod]=1;
dest.push_back(v1[id1]);
}
++id1;
}
while(id2<(int)v2.size()){
if(!folosit[v2[id2].nod]){
folosit[v2[id2].nod]=1;
dest.push_back(v2[id2]);
}
++id2;
}
for(auto [nod,cnt] : dest)
folosit[nod]=0;
while((int)dest.size()>SQRT+1)
dest.pop_back();
}
void do_precalc(){
int i;
for(i=1;i<=n;++i){
for(auto vec : in[i]){
vector<path>aux=precalc[vec];
for(auto &[nod,cnt] : aux)
++cnt;
merge_(precalc[i],precalc[i],aux);
}
if(precalc[i].size()<=SQRT)
precalc[i].push_back({i,0});
}
}
bool ocupat[MAX];
int query_mic(int party,vector<int>busy){
for(auto nod : busy)
ocupat[nod]=1;
int answer=-1;
for(auto [nod,cnt] : precalc[party])
if(!ocupat[nod]){
answer=cnt;
break;
}
for(auto nod : busy)
ocupat[nod]=0;
return answer;
}
int dp[MAX];
void maxself(int& x,int val){
if(x<val)
x=val;
}
int query_mare(int party,vector<int>busy){
for(auto nod : busy)
ocupat[nod]=1;
int i;
for(i=1;i<=party;++i){
if(ocupat[i])
dp[i]=-INF;
else
dp[i]=0;
for(auto vec : in[i])
maxself(dp[i],dp[vec]+1);
}
maxself(dp[party],-1);
for(auto nod : busy)
ocupat[nod]=0;
return dp[party];
}
void process_queries(){
while(q--){
int party,sz;
cin>>party>>sz;
vector<int>busy;
int i;
for(i=1;i<=sz;++i){
int ocup;
cin>>ocup;
busy.push_back(ocup);
}
if(sz<=SQRT)
cout<<query_mic(party,busy)<<'\n';
else
cout<<query_mare(party,busy)<<'\n';
}
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
read();
do_precalc();
process_queries();
return 0;
}
