#include <bits/stdc++.h>
using namespace std;
constexpr int SQ = 100;
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, m, q;
cin >> n >> m >> q;
vector<vector<int>> rg(n);
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
rg[--v].push_back(--u);
}
vector<vector<pair<int, int>>> path_sizes(n);
vector<int> from(n, -1);
for (int i = 0; i < n; i++) {
path_sizes[i].push_back({0, i});
vector<int> from_indicies;
for (int j : rg[i]) {
for (auto [dist, idx] : path_sizes[j]) {
if (from[idx] == -1) {
from_indicies.push_back(idx);
from[idx] = dist + 1;
} else {
from[idx] = max(from[idx], dist + 1);
}
}
}
for (int j : from_indicies) { path_sizes[i].push_back({from[j], j}); }
sort(path_sizes[i].rbegin(), path_sizes[i].rend());
while (path_sizes[i].size() > SQ) { path_sizes[i].pop_back(); }
for (int j : from_indicies) { from[j] = -1; }
}
vector<bool> blocked(n);
for (int query = 0; query < q; query++) {
int t, y;
cin >> t >> y;
t--;
vector<int> c(y);
for (int i = 0; i < y; i++) {
cin >> c[i];
blocked[--c[i]] = true;
}
int ans = -1;
if (y >= SQ) {
vector<int> dp(t + 1, -1);
dp[t] = 0;
for (int i = t; i >= 0; i--) {
if (dp[i] == -1) { continue; }
if (!blocked[i]) { ans = max(ans, dp[i]); }
for (int j : rg[i]) { dp[j] = max(dp[j], dp[i] + 1); }
}
} else {
for (auto [dist, idx] : path_sizes[t]) {
if (!blocked[idx]) {
ans = dist;
break;
}
}
}
cout << ans << "\n";
for (int i : c) { blocked[i] = false; }
}
}
