#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 1, Y = 150;
int dp[N];
bitset<N> v;
vector<int> adj[N];
vector<pair<int, int>> best[N];
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, q;
cin >> n >> m >> q;
while (m--) {
int s, e;
cin >> s >> e;
adj[e].push_back(s);
}
for (int i = 1; i <= n; i++) {
priority_queue<array<int, 3>> pq;
for (int j : adj[i])
pq.emplace(array{best[j][0].first, j, 1});
while (!pq.empty() && best[i].size() < Y) {
auto [l, j, idx] = pq.top();
pq.pop();
int k = best[j][idx - 1].second;
if (!v[k]) {
best[i].emplace_back(l + 1, k);
v[k] = true;
}
if (idx < (int)best[j].size())
pq.emplace(array{best[j][idx].first, j, idx + 1});
}
for (auto &[l, j] : best[i])
v[j] = false;
if (best[i].size() < Y)
best[i].emplace_back(0, i);
}
while (q--) {
int t, y;
cin >> t >> y;
vector<int> c(y);
for (int &i : c)
cin >> i;
int ans = -1;
if (y < Y) {
for (int i : c)
v[i] = true;
for (auto &[l, i] : best[t]) {
if (!v[i]) {
ans = l;
break;
}
}
for (int i : c)
v[i] = false;
} else {
memset(dp, 0, sizeof(dp));
for (int i : c)
dp[i] = -1;
for (int i = 1; i <= t; i++)
for (int j : adj[i])
if (dp[j] != -1)
dp[i] = max(dp[i], dp[j] + 1);
ans = dp[t];
}
cout << ans << '\n';
}
}
