#include <bits/stdc++.h>
using namespace std;
using PII = pair<int,int>;
#define rall(a) rbegin(a), rend(a)
#define f first
#define s second
constexpr int maxN = 1e5, step = 100;
vector<int> edges[maxN + 1];
vector<PII> dp[maxN + 1];
int dist[maxN + 1];
bitset<maxN + 1> busy;
int main() {
cin.tie(0) -> sync_with_stdio(0);
int n, m, q; cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int a, b; cin >> a >> b;
edges[b].push_back(a);
}
for (int i = 1; i <= n; i++) dist[i] = -1;
for (int i = 1; i <= n; i++) {
dp[i].push_back({0, i});
vector<int> indices;
for (int e: edges[i]) {
for (auto& [x, ind]: dp[e]) {
if (dist[ind] == -1) {
indices.push_back(ind);
dist[ind] = x + 1;
} else {
dist[ind] = max(dist[ind], x + 1);
}
}
}
for (int ind: indices) dp[i].push_back({dist[ind], ind});
sort(rall(dp[i]));
while (dp[i].size() > step) dp[i].pop_back();
for (int ind: indices) dist[ind] = -1;
}
while (q--) {
int t, y, ans = -1; cin >> t >> y;
busy.reset();
for (int i = 0; i < y; i++) {
int b; cin >> b;
busy[b] = true;
}
if (y <= step) { // search through dp
for (auto& [x, ind]: dp[t]) {
if (!busy[ind]) {
ans = x;
break;
}
}
} else {
vector<int> maxDist(t + 1, -1);
maxDist[t] = 0;
for (int i = t; i >= 0; i--) {
if (maxDist[i] == -1) { continue; }
if (!busy[i]) { ans = max(ans, maxDist[i]); }
for (int j : edges[i]) { maxDist[j] = max(maxDist[j], maxDist[i] + 1); }
}
}
cout << ans << '\n';
}
}
