#include <bits/stdc++.h>
using namespace std;
#define sz(v) (int)v.size()
const int MAXN = 1e5+5;
vector<int> adj[MAXN], radj[MAXN], ini[MAXN], dist[MAXN];
int mx[MAXN], marc[MAXN], val[MAXN], g[MAXN], in[MAXN];
bool cmp(int a, int b){
return mx[a] > mx[b];
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int B = 158;
int n,m,q; cin>>n>>m>>q;
for(int i = 1; i <= m; i++){
int a,b; cin>>a>>b;
adj[a].push_back(b); in[b] ++;
radj[b].push_back(a);
}
for(int i = 1; i <= n; i++){
vector<int> v;
v.push_back(i);
for(int viz : radj[i]){
for(int j = 0; j < sz(ini[viz]); j++){
if(mx[ ini[viz][j] ] == 0){
mx[ ini[viz][j] ] = dist[viz][j] + 1;
v.push_back( ini[viz][j] );
}else{
mx[ ini[viz][j] ] = max( mx[ ini[viz][j] ], dist[viz][j] + 1);
}
}
}
sort(v.begin(),v.end(),cmp);
for(int j = 0; j < B; j++){
if(mx[v[j]] == 0 && v[j] != i)break;
ini[i].push_back(v[j]); dist[i].push_back( mx[v[j]] );
mx[v[j]] = 0;
}
}
for(int id = 1; id <= q; id++){
int v, qtd; cin>>v>>qtd;
vector<int> block;
for(int i = 0; i < qtd; i++){
int x; cin>>x;
block.push_back(x);
marc[x] = 1;
}
if(qtd >= B){
queue<int> q;
for(int i = 1; i <= n; i++){
val[i] = -1; g[i] = in[i];
if(in[i] == 0){
q.push(i);
val[i] = (marc[i]) ? -1 : 0;
}
}
while(!q.empty()){
int x = q.front(); q.pop();
if(!marc[x])val[x] = max(val[x], 0);
for(int viz : adj[x]){
if(val[x] != -1)val[viz] = max(val[viz], val[x]+1);
g[viz]--;
if(g[viz] == 0)q.push(viz);
}
}
cout<<val[v]<<"\n";
}else{
int ok = 0;
for(int i = 0; i < sz(dist[v]); i++)
if(!marc[ ini[v][i] ]){ok = 1; cout<<dist[v][i]<<"\n"; break; }
if(!ok)cout<<"-1\n";
}
for(int x : block)marc[x] = 0;
}
}
