#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
#include<limits.h>
#include<math.h>
#include<map>
#include<set>
#include<unordered_map>
#include<unordered_set>
#include<iomanip>
#include<cstring>
#include<random>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using namespace std;
int n,m,q;
vector<int>nodes[100000];
vector<int>rev[100000];
vector<pair<int,int>>farthest[100000]; // (dist,node)
const int CHUNK_SIZE=500;
int solve(int src,vector<int>blocked){
vector<int>in(n);
vector<int>res(n);
queue<int>q;
for(int i=0;i<n;i++){
in[i]=(int)rev[i].size();
if(in[i]==0)
q.push(i);
}
for(int i:blocked)
res[i]=-1e9;
while(q.size()){
int node=q.front();
q.pop();
for(int ne:rev[node])
res[node]=max(res[node],res[ne]+1);
for(int ne:nodes[node]){
in[ne]--;
if(in[ne]==0)
q.push(ne);
}
}
return max(-1,res[src]);
}
void setup(){
vector<int>in(n);
queue<int>q;
for(int i=0;i<n;i++){
in[i]=(int)rev[i].size();
if(in[i]==0)
q.push(i);
}
while(q.size()){
int node=q.front();
q.pop();
vector<int>it(rev[node].size());
while(farthest[node].size()<CHUNK_SIZE){
int nxt=-1;
for(int i=0;i<(int)it.size();i++){
if(it[i]==(int)farthest[rev[node][i]].size())
continue;
if(nxt==-1||farthest[rev[node][i]][it[i]].first>farthest[rev[node][nxt]][it[nxt]].first)
nxt=i;
}
if(nxt==-1)
break;
farthest[node].push_back(farthest[rev[node][nxt]][it[nxt]]);
farthest[node].back().first++;
it[nxt]++;
}
if(farthest[node].size()<CHUNK_SIZE)
farthest[node].emplace_back(0,node);
for(int ne:nodes[node]){
in[ne]--;
if(in[ne]==0)
q.push(ne);
}
}
}
void solve(){
cin>>n>>m>>q;
for(int i=0;i<m;i++){
int a,b;
cin>>a>>b;
a--;b--;
nodes[a].push_back(b);
rev[b].push_back(a);
}
setup();
while(q--){
int src,k;
cin>>src>>k;
src--;
vector<int>blocked(k);
for(int&i:blocked){
cin>>i;
i--;
}
unordered_set<int>s(blocked.begin(),blocked.end());
int res=-1;
for(auto[d,i]:farthest[src]){
if(s.count(i)==0){
res=d;
break;
}
}
if(res!=-1||farthest[src].size()!=CHUNK_SIZE){
cout<<res<<"\n";
continue;
}
cout<<solve(src,blocked)<<"\n";
}
}
int main(){
ios::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
//freopen("/Users/jakob/cp_testing/test.txt","r",stdin);//freopen("output.out","w",stdout);
int t=1;//cin>>t;
while(t--)solve();
return 0;
}
/*
5 6 3
1 2
2 4
3 4
1 3
3 5
4 5
4 1 1
5 2 2 3
2 3 1 4 5
1
3
0
*/
