#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, q; cin >> n >> m >> q;
int bl = 220;
vector<vector<int>> to(n), into(n);
for (int i = 0; i < m; ++i) {
int a, b; cin >> a >> b;
to[--a].push_back(--b);
into[b].push_back(a);
}
vector<vector<pair<int, int>>> best(n);
vector<int> from(n, -1);
for (int i = 0; i < n; ++i) {
from[i] = 0;
vector<int> idxs = {i};
for (int j : into[i]) {
for (pair<int, int> k : best[j]) {
if (from[k.second] == -1) {
from[k.second] = k.first + 1;
idxs.push_back(k.second);
} else {
from[k.second] = max(from[k.second], k.first + 1);
}
}
}
for (int j : idxs) {
best[i].push_back({from[j], j});
}
sort(best[i].rbegin(), best[i].rend());
while (best[i].size() > bl) best[i].pop_back();
for (int j : idxs) {
from[j] = -1;
}
}
vector<bool> nouse(n);
vector<int> mx(n);
vector<int> c(n);
while (q--) {
int t, y; cin >> t >> y;
for (int i = 0; i < y; ++i) {
cin >> c[i];
--c[i];
nouse[c[i]] = true;
}
--t;
if (y >= bl) {
int ans = -1;
for (int j = t; j >= 0; --j) {
mx[j] = (j == t ? 0 : -1);
for (int k : to[j]) {
if (k <= t && mx[k] != -1) mx[j] = max(mx[j], mx[k] + 1);
}
if (!nouse[j]) ans = max(ans, mx[j]);
}
cout << ans << '\n';
} else {
auto it = best[t].begin();
while (it != best[t].end() && nouse[it->second]) {
++it;
}
if (it == best[t].end()) {
cout << "-1\n";
} else {
cout << it->first << '\n';
}
}
for (int i = 0; i < y; ++i) {
nouse[c[i]] = false;
}
}
return 0;
}
