#include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
#include <numeric>
#include <stack>
#include <chrono>
using namespace std;
void fast_io(){
// freopen("", "r", stdin);
// freopen("", "w", stdout);
ios::sync_with_stdio(0);
cin.tie(); cout.tie();
cout << setprecision(9);
}
#define int long long
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define fi first
#define se second
const int N = 1e5 + 5;
int n, m, q, indeg[N];
vector<int> adj[N];
vector<pair<int, int>> L[N];
vector<pair<int,int>> merge(const vector<pair<int,int>>& A, const vector<pair<int,int>>& B) {
static pair<int,int> tmp[700]; // temporary buffer
int k = 0;
for(auto &x : A) tmp[k++] = {x.first + 1, x.second};
for(auto &y : B) tmp[k++] = {y.first, y.second};
sort(tmp, tmp + k, [](auto &a, auto &b){ return a.second < b.second; });
vector<pair<int,int>> out;
out.reserve(300);
for(int i = 0; i < k; ) {
int src = tmp[i].second, best = tmp[i].first, j = i + 1;
while(j < k && tmp[j].second == src) {
best = max(best, tmp[j].first);
j++;
}
out.push_back({best, src});
i = j;
}
sort(out.rbegin(), out.rend()); // sort descending by length
if(out.size() > 300) out.resize(300);
return out;
}
void init(){
int IN[N];
for (int i = 1; i <= n; i++) IN[i] = indeg[i];
queue<int> q;
for (int i = 1; i <= n; i++){
L[i].push_back({0, i});
if (IN[i] == 0) q.push(i);
}
while (q.size()){
int u = q.front(); q.pop();
for (auto v : adj[u]){
L[v] = merge(L[u], L[v]);
--IN[v];
if (IN[v] == 0) q.push(v);
}
}
}
void solve() {
cin >> n >> m >> q;
for (int i = 1; i <= m; i++){
int u, v; cin >> u >> v;
indeg[v]++;
adj[u].push_back(v);
}
init();
for (int i = 1; i <= n; i++) sort(rall(L[i]));
for (int Q = 1; Q <= q; Q++){
int T, Y; cin >> T >> Y;
int C[Y + 1];
map<int, bool> c;
for (int i = 1; i <= Y; i++) {
cin >> C[i];
c[C[i]] = 1;
}
if (Y <= 300)
{
bool bb = 0;
int S = min(300ll, (int) L[T].size());
for (int i = 0; i < S; i++){
if (!c[L[T][i].second]){
cout << L[T][i].first << endl;
bb = 1;
break;
}
}
if (!bb) cout << -1 << endl;
}
else
{
queue<int> q;
int IN[N] = {}, ans[N] = {};
for (int i = 1; i <= Y; i++){
ans[C[i]] = -1e18;
}
for (int i = 1; i <= n; i++) IN[i] = indeg[i];
for (int i = 1; i <= n; i++){
if (IN[i] == 0) q.push(i);
}
while (q.size()){
int u = q.front(); q.pop();
for (auto v : adj[u]){
ans[v] = max(ans[v], ans[u] + 1);
IN[v]--;
if (IN[v] == 0) q.push(v);
}
}
if (ans[T] < 0) cout << -1 << endl;
else cout << ans[T] << endl;
}
}
return;
}
signed main() {
fast_io();
srand(chrono::steady_clock::now().time_since_epoch().count());
int tc = 1;
// cin >> tc;
while (tc--) solve();
return 0;
}
