#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 5;
const int MAXS = 320;
vector<int> adj[MAXN], rev[MAXN];
vector<pair<int, int>> caras[MAXN];
int in[MAXN], bosta[MAXN], best[MAXN];
pair<int, int> revIn[MAXN];
bool mark[MAXN], blocked[MAXN], valid[MAXN];
void merge(vector<pair<int, int>>& a, vector<pair<int, int>> b) {
vector<pair<int, int>> result;
int tamA = (int) a.size();
int tamB = (int) b.size();
int i = 0, j = 0, cnt = 0;
for (; i < tamA && j < tamB && cnt < MAXS + 1;) {
if (mark[a[i].second]) {
i++;
continue;
}
if (mark[b[j].second]) {
j++;
continue;
}
if (a[i].first > b[j].first + 1) {
mark[a[i].second] = true;
result.push_back(a[i++]);
} else {
mark[b[j].second] = true;
result.emplace_back(b[j].first + 1, b[j].second);
j++;
}
cnt++;
}
for (; i < tamA && cnt < MAXS + 1; i++) {
if (mark[a[i].second]) continue;
cnt++;
result.push_back(a[i]);
}
for (; j < tamB && i + j < MAXS + 1; j++) {
if (mark[b[j].second]) continue;
cnt++;
result.emplace_back(b[j].first + 1, b[j].second);
}
for (i = 0; i < (int) result.size(); i++) {
mark[result[i].second] = false;
}
a = result;
}
int main(){
ios::sync_with_stdio(false);
cin.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].push_back(b);
rev[b].push_back(a);
in[b]++;
revIn[a].first++;
}
for (int i = 1; i <= n; i++) {
revIn[i].second = revIn[i].first;
}
vector<int> lista;
for (int i = 1; i <= n; i++) {
caras[i].emplace_back(0, i);
if (!in[i]) lista.push_back(i);
}
for (int i = 0; i < (int) lista.size(); i++) {
int cur = lista[i];
for (int nxt : adj[cur]) {
in[nxt]--;
if (!in[nxt]) lista.push_back(nxt);
merge(caras[nxt], caras[cur]);
}
}
for (int i = 0; i < q; i++) {
int t, y;
cin >> t >> y;
for (int j = 0; j < y; j++) {
cin >> bosta[j];
blocked[bosta[j]] = true;
}
if (y > MAXS) {
lista.clear();
for (int j = 1; j <= n; j++) {
best[j] = -1;
revIn[j].first = revIn[j].second;
if (!revIn[j].first) lista.push_back(j);
}
valid[t] = true;
best[t] = 0;
for (int j = 0; j < (int) lista.size(); j++) {
int cur = lista[j];
for (int nxt : rev[cur]) {
revIn[nxt].first--;
if (!revIn[nxt].first) lista.push_back(nxt);
if (valid[cur]) {
valid[nxt] = true;
best[nxt] = max(best[nxt], best[cur] + 1);
}
}
}
int ans = -1;
for (int j = 1; j <= t; j++) {
valid[j] = false;
if (!blocked[j]) ans = max(ans, best[j]);
}
cout << ans << '\n';
} else {
int ans = -1;
for (auto x : caras[t]) {
if (!blocked[x.second]) {
ans = x.first;
break;
}
}
cout << ans << '\n';
}
for (int j = 0; j < y; j++) {
blocked[bosta[j]] = false;
}
}
// for (int i = 1; i <= n; i++) {
// cout << i << " -> ";
// for (auto x : caras[i]) {
// cout << "(" << x.first << ", " << x.second << "), ";
// }
// cout << '\n';
// }
return 0;
}
