#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int maxn = 1e5 + 100;
vector<int> a[maxn];
int key[maxn];
set<pii> st[maxn];
int addv[maxn];
set<int> quer[maxn];
vector<int> ques[maxn];
int ans[maxn];
int cnt = 1;
// new: stored value for node inside its component (the first element of pair in that component's set)
int val_stored[maxn];
void dfs(int x){
if(a[x].empty()){
key[x] = cnt;
addv[cnt] = 0;
st[cnt].insert({0,x});
val_stored[x] = 0; // initialize
cnt++;
return;
}
vector<int> pd;
int maxi = 0;
for(auto u : a[x]){
if(maxi == 0){
maxi = key[u];
continue;
}
if(st[key[u]].size() > st[maxi].size()){
pd.push_back(maxi);
maxi = key[u];
}
else pd.push_back(key[u]);
}
key[x] = maxi;
addv[maxi] += 1;
// merge other component sets into maxi, with proper updates to keep nodes unique and values maximal
for(auto u : pd){
if(u == maxi) continue;
if(st[u].empty()) continue;
// iterate over a copy because we'll clear st[u]
vector<pii> items;
items.reserve(st[u].size());
for(auto p : st[u]) items.push_back(p);
for(auto p : items){
int stored_in_u = p.first;
int node = p.second;
// effective value of node in component u:
int effective = stored_in_u + addv[u];
if(key[node] == maxi){
// node already exists in maxi: compare effective values and keep the larger one
int old_stored = val_stored[node];
int old_effective = old_stored + addv[maxi];
if(effective > old_effective){
// erase old pair and insert new one with updated stored
st[maxi].erase({old_stored, node});
int new_stored = effective - addv[maxi];
st[maxi].insert({new_stored, node});
val_stored[node] = new_stored;
}
// else do nothing (old value is better)
} else {
// move node into maxi
int new_stored = effective - addv[maxi];
st[maxi].insert({new_stored, node});
val_stored[node] = new_stored;
key[node] = maxi;
}
}
st[u].clear();
}
// insert x itself (distance 0)
st[maxi].insert({-addv[maxi], x});
val_stored[x] = -addv[maxi];
key[x] = maxi;
for(int i = 0; i < (int)ques[x].size(); i++){
int id = ques[x][i];
ans[id] = -1;
for(auto it = st[maxi].rbegin(); it != st[maxi].rend(); ++it){
int node = it->second;
if(!quer[id].count(node)){
ans[id] = it->first + addv[maxi];
break;
}
}
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n,m,q;
cin >> n >> m >> q;
for(int i = 1; i <= m; i++){
int u,v;
cin >> u >> v;
a[v].push_back(u);
}
for(int i = 1; i <= q; i++){
int x,y;
cin >> x >> y;
ques[x].push_back(i);
for(int j = 0; j < y; j++){
int z;
cin >> z;
quer[i].insert(z);
}
ans[i] = -1;
}
for(int i = 1; i <=n; i++) dfs(i);
for(int i = 1; i <= q; i++){
if(ans[i]>1)
cout << ans[i]-1 << "\n";
else
cout << ans[i] << "\n";
}
return 0;
}
