#include <bits/stdc++.h>
using namespace std;
#define int long long
void dbg(){cout<<"\033[0m";}
template<typename T,typename... args>
void dbg(T f,args... a){cout<<"\033[95m"<<f;dbg(a...);}
#define dbg(...)
int n,m,q;
const int K = 250;
vector<int> back[(int)1e5+5];
int dp[(int)1e5+5];
// store up to K longest path to any node.
vector<pair<int,int>> path[(int)1e5+5];
void add(const pair<int,int> &x,vector<pair<int,int>> &V){
auto it = lower_bound(V.begin(),V.end(),x,greater<pair<int,int>>());
if(it != V.end() && *it == x)return;
V.insert(it,x);
if(V.size() > K)V.resize(K);
}
signed main(){
cin>>n>>m>>q;
for(int i=1;i<=m;i++){
int u,v;cin>>u>>v;
back[v].push_back(u);
}
for(int i=1;i<=n;i++){
add({0ll,i},path[i]);
for(int v:back[i]){
for(auto g:path[v]){
add({g.first+1,g.second},path[i]);
}
}
}
for(int i=1;i<=n;i++){
dbg(i," : \n");
for(auto g:path[i])dbg(g.first,' ',g.second,"\n");
}
while(q--){
int T,Y;cin>>T>>Y;
set<int> NO;
for(int i=1;i<=Y;i++){
int x;cin>>x;NO.insert(x);
}
int ans = -1;
if(Y>=K){
for(int i=1;i<=T;i++){
int ok = (NO.find(i) == NO.end());
dp[i] = -1 + ok;
for(int v:back[i]){
if(dp[v] != -1)dp[i] = max(dp[i],dp[v]+1);
}
}
ans = dp[T];
}
else{
for(auto x:path[T]){
if(NO.find(x.second) == NO.end()){
ans = x.first;
break;
}
}
}
cout<<ans<<'\n';
}
return 0;
}
