#include <iostream>
#include <vector>
using namespace std;
const int BLOCK_SIZE = 320;
const int INF = 1e9;
int main() {
// Optimize standard I/O operations for performance
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m, q;
if (!(cin >> n >> m >> q)) return 0;
vector<vector<int>> rev_adj(n + 1);
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
rev_adj[v].push_back(u);
}
vector<vector<pair<int, int>>> top_paths(n + 1);
// Global seen array and a timer to check distinct origins in O(1)
vector<int> seen(n + 1, 0);
int timer = 0;
// Optimized Precomputation phase using Two-Pointer Merge
for (int v = 1; v <= n; v++) {
// A node can always reach itself with distance 0
top_paths[v].push_back({0, v});
for (int u : rev_adj[v]) {
timer++; // Unique token for this specific edge merge
vector<pair<int, int>> merged;
int i = 0, j = 0;
int sz_v = top_paths[v].size();
int sz_u = top_paths[u].size();
// Merge two sorted arrays up to BLOCK_SIZE elements
while (merged.size() < BLOCK_SIZE && (i < sz_v || j < sz_u)) {
// Pick from top_paths[v] if top_paths[u] is exhausted,
// OR if top_paths[v]'s current distance is greater/equal.
if (j == sz_u || (i < sz_v && top_paths[v][i].first >= top_paths[u][j].first + 1)) {
int origin = top_paths[v][i].second;
if (seen[origin] != timer) {
seen[origin] = timer;
merged.push_back(top_paths[v][i]);
}
i++;
} else {
int origin = top_paths[u][j].second;
if (seen[origin] != timer) {
seen[origin] = timer;
merged.push_back({top_paths[u][j].first + 1, origin});
}
j++;
}
}
// Update top_paths[v] with the newly merged top candidates
top_paths[v] = merged;
}
}
vector<int> dist(n + 1, -1);
vector<bool> blocked(n + 1, false);
// Query phase remains exactly the same
for (int i = 0; i < q; i++) {
int target, y_count;
cin >> target >> y_count;
vector<int> y(y_count);
for (int j = 0; j < y_count; j++) {
cin >> y[j];
blocked[y[j]] = true;
}
if (y_count >= BLOCK_SIZE) {
// Heavy Query: O(N + M) DP
for (int v = 1; v <= target; v++) {
dist[v] = blocked[v] ? -INF : 0;
for (int u : rev_adj[v]) {
if (dist[u] != -INF) {
dist[v] = max(dist[v], dist[u] + 1);
}
}
}
cout << (dist[target] < 0 ? -1 : dist[target]) << "\n";
} else {
// Light Query: O(B) Lookup
int ans = -1;
for (auto p : top_paths[target]) {
if (!blocked[p.second]) {
ans = p.first;
break;
}
}
cout << ans << "\n";
}
for (int j = 0; j < y_count; j++) {
blocked[y[j]] = false;
}
}
return 0;
}
