#include <iostream>
#include <vector>
#include <algorithm>
#include <string.h>
using namespace std;
const int sqrt = 500;
int n, m, q;
vector <int> parent[100005];
struct st {
int idx, d;
bool operator < (const st &other) const {
return d > other.d;
}
};
vector <int> canGo;
vector <st> dist[100005], all;
st visited[100005];
int busy[100005], dp[100005];
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int u, v; cin >> u >> v;
parent[v].push_back(u);
}
for (int i = 1; i <= n; i++) {
canGo.clear();
all.clear();
canGo.push_back(i);
visited[i] = {i, 0};
for (auto p : parent[i]) {
for (auto go : dist[p]) {
if (visited[go.idx].idx != i) {
visited[go.idx] = {i, 1 + go.d};
canGo.push_back(go.idx);
}
else {
if (visited[go.idx].d < 1 + go.d) {
visited[go.idx].d = 1 + go.d;
}
}
}
}
for (auto go : canGo) {
all.push_back({go, visited[go].d});
}
sort(all.begin(), all.end());
for (int j = 0; j < min((int)all.size(), sqrt); j++) {
dist[i].push_back(all[j]);
}
}
for (int i = 1; i <= q; i++) {
int t, y; cin >> t >> y;
for (int j = 0; j < y; j++) {
int x; cin >> x;
busy[x] = i;
}
if (y < sqrt) {
bool found = false;
for (auto e : dist[t]) {
if (busy[e.idx] != i) {
cout << e.d << '\n';
found = true;
break;
}
}
if (!found) cout << -1 << '\n';
}
else {
memset(dp, -1, sizeof(dp));
for (int j = 1; j <= t; j++) {
if (busy[j] != i) dp[j] = 0;
for (auto p : parent[j]) {
if (dp[p] == -1) continue;
else dp[j] = max(dp[j], dp[p] + 1);
}
}
cout << dp[t] << '\n';
}
}
return 0;
}
