#include <bits/stdc++.h>
#define ff first
#define ss second
#define all(x) x.begin(),x.end()
#define pb push_back
using namespace std;
const int N=1e5+5,sq=350;
vector <pair <int,int> > cct[N];
vector <int> g[N];
signed main(){
int n,m,q;
cin>>n>>m>>q;
for(int i=0;i<m;i++){
int u,v;
cin>>u>>v;
g[v].pb(u);
}
vector <int> d(n+1),ld(n+1),can;
for(int i=1;i<=n;i++){
d[i]=0;
can.pb(i);
for(auto edg : g[i]){
for(auto x : cct[edg]){
if(ld[x.ss]==i){
d[x.ss]=max(d[x.ss],x.ff+1);
}
else{
d[x.ss]=x.ff+1;
ld[x.ss]=i;
can.pb(x.ss);
}
}
}
sort(all(can),[&](int a, int b){return d[a]>d[b];});
for(int j=0;j<min((int)can.size(),sq);j++){
int x=can[j];
cct[i].pb({d[x],x});
}
/*cout<<i<<"\n";
for(auto x :cct[i])cout<<x.ff<<" "<<x.ss<<"\n";
cout<<"\n";*/
can.clear();
}
vector <int> no(n+1),dp(n+1);
while(q--){
int t,s;
cin>>t>>s;
vector <int> a(s);
for(int i=0;i<s;i++){
cin>>a[i];
no[a[i]]=1;
dp[a[i]]=-1e9;
}
int ans=-1;
if(s<sq){
for(auto x : cct[t]){
if(!no[x.ss]){
ans=x.ff;
break;
}
}
}
else{
for(int i=1;i<=t;i++){
for(auto edg : g[i]){
dp[i]=max(dp[i],dp[edg]+1);
}
}
ans=max(ans,dp[t]);
for(int i=1;i<=t;i++){
dp[i]=0;
}
}
cout<<ans<<"\n";
for(int i=0;i<s;i++){
no[a[i]]=0;
dp[a[i]]=0;
}
}
}
/*
*/
