#include<bits/stdc++.h>
using namespace std;
#define pb push_back
vector<int> adj[100001];
vector<int> badj[100001];
int indeg[100001];
int BLKSZ=300;
vector<pair<int,int>> best[100001];
int dp[100010];
int bannolt[100010];
int dfs(int x) {
if(dp[x]!=-2) {
return dp[x];
}
int ans=-1;
if(!bannolt[x]) {
ans=0;
}
for(auto i:badj[x]) {
if(dfs(i)>=0) {
ans=max(ans, dfs(i)+1);
}
}
// cerr<<x<<"->"<<ans<<" | "<<bannolt[x]<<"\n";
return dp[x]=ans;
}
int volt[100010], voltind=0;
vector<pair<int,int>> rendez(vector<int>& miket) {
/*for(auto i:miket) {
cerr<<i<<" ";
}cerr<<" RENDEZ\n";*/
if(miket.size()==0) {
return {};
}
if(miket.size()==1) {
vector<pair<int,int>> cpy=best[miket[0]];
for(auto& i:cpy) i.first++;
return cpy;
}
vector<int> L, R;
for(int i=0;i<(int)miket.size()/2;++i) {
L.push_back(miket[i]);
}
for(int i=(int)miket.size()/2;i<(int)miket.size();++i) {
R.push_back(miket[i]);
}
auto l=rendez(L), r=rendez(R);
int i=0, j=0;
voltind++;
vector<pair<int,int>> ans;
while((i<(int)l.size() || j<(int)r.size()) && (int)ans.size()<BLKSZ) {
//cerr<<i<<" "<<j<<"\n";cerr.flush();
while(i<(int)l.size() && volt[l[i].second]==voltind) i++;
while(j<(int)r.size() && volt[r[j].second]==voltind) j++;
if(i<(int)l.size() && (j==(int)r.size() || l[i].first>=r[j].first)) {
ans.push_back(l[i++]);
assert(volt[ans.back().second]!=voltind);
volt[ans.back().second]=voltind;
}else if(j<(int)r.size()) {
ans.push_back(r[j++]);
assert(volt[ans.back().second]!=voltind);
volt[ans.back().second]=voltind;
}
//cerr<<i<<" "<<j<<"\n";cerr.flush();
}
/*
for(auto i:ans) {
cerr<<i.first<<" "<<i.second<<";";
}cerr<<"!\n";
*/
return ans;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n,m,q;
cin>>n>>m>>q;
for(int i=0;i<m;++i) {
int a,b;
cin>>a>>b;
adj[a].pb(b);
badj[b].pb(a);
indeg[b]++;
}
vector<pair<int,int>> st;
for(int i=1;i<=n;++i) {
if(indeg[i]==0) st.push_back({indeg[i], i});
}
while(!st.empty()) {
pair<int,int> akt=st.back();
st.pop_back();
//priority_queue<pair<int,int>> pq; //(dist, honnan)
//pq.push({0, akt.second});
//cerr<<akt.second<<"==========\n";
best[akt.second]=rendez(badj[akt.second]);
if((int)best[akt.second].size()<BLKSZ) {
best[akt.second].push_back({0, akt.second});
}
/*lst.push_back({0, akt.second});
for(auto i:badj[akt.second]) {
for(auto j:best[i]) {
lst.push_back({j.first+1, j.second});
}
}
sort(lst.rbegin(), lst.rend());
voltind++;
for(int i=0, j=0;i<(int)lst.size()&&j<BLKSZ;++i) {
if(volt[lst[i].second]!=voltind) {
volt[lst[i].second]=voltind;
j++;
best[akt.second].push_back(lst[i]);
}
}*/
for(auto i:adj[akt.second]) {
indeg[i]--;
if(indeg[i]==0) st.pb({indeg[i], i});
}
}
/*for(int i=1;i<=n;++i) {
cerr<<i<<": ";
for(auto j:best[i]) {
cerr<<j.first<<" "<<j.second<<";";
}cerr<<"\n";
}*/
for(int i=0;i<q;++i) {
int place;
int cnt;
cin>>place>>cnt;
vector<int> banned(cnt);
for(int i=0;i<cnt;++i) {
cin>>banned[i];
bannolt[banned[i]]=1;
}
bool ok=false;
for(int j=0;j<(int)best[place].size();++j) {
if(!bannolt[best[place][j].second]) {
ok=true;
cout<<best[place][j].first<<"\n";
break ;
}
}
if(ok) {
for(int i=0;i<cnt;++i) {
bannolt[banned[i]]=0;
}
continue ;
}else if((int)best[place].size()<BLKSZ) {
cout<<"-1\n";
for(int i=0;i<cnt;++i) {
bannolt[banned[i]]=0;
}
continue ;
}
for(int i=1;i<=place;++i) {
dp[i]=-2;
}
cout<<dfs(place)<<"\n";
for(int i=0;i<cnt;++i) {
bannolt[banned[i]]=0;
}
}
return 0;
}
