#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair<int,int>
#define fir first
#define sec second
#define pb push_back
const int maxn=1e5;
const int mx=200;
int n,m,qu;
vector<int>adj[maxn+2];
ii dist[maxn+2];
vector<ii>path[maxn+2];
void precom(){
for(int q=1;q<=n;q++){
vector<int>node;
node.pb(q);
dist[q]={0,q};
for(auto x : adj[q]){
for(auto [brp,idx] : path[x]){
if(dist[idx].sec!=q){
dist[idx]={brp+1,q};
node.pb(idx);
}
else{
dist[idx].fir=max(dist[idx].fir,brp+1);
}
}
}
for(auto x : node){
path[q].pb({dist[x].fir,x});
//if(q==4)cout<<dist[x].fir<<"K"<<x<<endl;
}
sort(path[q].rbegin(),path[q].rend());
while(path[q].size()>mx){
path[q].pop_back();
}
}
}
bool skip[maxn+2];
int val[maxn+2];
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>m>>qu;
for(int q=1;q<=m;q++){
int u,v;
cin>>u>>v;
adj[v].pb(u);
}
precom();
while(qu--){
int city,brp;
cin>>city>>brp;
vector<int>apa;
for(int q=1;q<=brp;q++){
int x;cin>>x;
apa.pb(x); skip[x]=true;
}
if(brp<mx){
int ans=-1;
for(auto [jrk,idx] : path[city]){
if(skip[idx])continue;
ans=jrk; break;
}
cout<<ans<<endl;
}
else{
for(int q=1;q<=n;q++){
val[q]=0;
}
for(int q=1;q<=city;q++){
for(auto x : adj[q]){
val[q]=max(val[x]+1,val[q]);
}
if(val[q]==0 && skip[q]){
val[q]=-1;
}
}
cout<<val[city]<<endl;
}
for(auto x : apa){
skip[x]=false;
}
}
}
