#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5 + 5;
const int K = 320;
vector<int> G[MAX_N];
vector<pair<int, int>> values[MAX_N];
int max_value[MAX_N], dp[MAX_N] = {};
bool vis[MAX_N] = {}, used[MAX_N] = {};
vector<int> order;
void topsort(int u) {
vis[u] = true;
for (int v : G[u]) {
if (!vis[v]) {
topsort(v);
}
}
order.push_back(u);
}
void DFS(int u) {
vis[u] = true;
for (int v : G[u]) {
if (!vis[v]) {
DFS(v);
}
}
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int N, M, Q;
cin >> N >> M >> Q;
for (int i = 0; i < M; i++) {
int u, v;
cin >> u >> v;
u--, v--;
G[v].push_back(u);
}
order.reserve(N);
for (int i = 0; i < N; i++) {
if (!vis[i]) {
topsort(i);
}
}
memset(max_value, -1, sizeof max_value);
for (int i : order) {
values[i] = {{0, i}};
for (int j : G[i]) {
vector<int> vals;
for (auto [val, v] : values[i]) {
vals.push_back(v);
max_value[v] = -val;
}
for (auto [val, v] : values[j]) {
if (max_value[v] == -1) {
vals.push_back(v);
}
max_value[v] = max(max_value[v], -val + 1);
}
values[i] = vector<pair<int, int>>();
for (int p : vals) {
values[i].push_back({-max_value[p], p});
}
if (values[i].size() > K) {
nth_element(values[i].begin(), values[i].begin() + K, values[i].end());
values[i].resize(K);
}
for (int p : vals) {
max_value[p] = -1;
}
}
}
for (int q = 0; q < Q; q++) {
int T, Y;
cin >> T >> Y;
T--;
vector<int> C(Y);
for (int &v : C) {
cin >> v;
used[--v] = true;
}
if (Y < K) {
int ans = -1;
for (auto [val, v] : values[T]) {
ans = -val > ans && !used[v] ? -val : ans;
}
cout << ans << "\n";
} else {
memset(dp, -1, sizeof dp);
for (int i : order) {
if (!used[i]) {
dp[i] = 0;
}
for (int j : G[i]) {
if (dp[j] != -1) {
dp[i] = dp[j] + 1 > dp[i] ? dp[j] + 1 : dp[i];
}
}
}
cout << dp[T] << "\n";
}
for (int v : C) {
used[v] = false;
}
}
}
