#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 5;
const int MAXS = 200;
vector<int> adj[MAXN], rev[MAXN];
vector<pair<int, int>> caras[MAXN], result;
int bosta[MAXN], dp[MAXN], valid[MAXN];
bool mark[MAXN], blocked[MAXN];
void merge(int a, int b) {
result.clear();
int j = 0;
for (int i = 0; i < (int) caras[a].size(); i++) {
for (; j < (int) caras[b].size() && caras[b][j].first + 1 > caras[a][i].first; j++) {
result.push_back({caras[b][j].first + 1, caras[b][j].second});
}
result.push_back(caras[a][i]);
}
for (; j < (int) caras[b].size(); j++) {
result.push_back({caras[b][j].first + 1, caras[b][j].second});
}
caras[a].clear();
for (auto x : result) {
if (!mark[x.second] && (int) caras[a].size() < MAXS + 1) {
caras[a].push_back(x);
mark[x.second] = true;
}
}
for (auto x : caras[a]) {
mark[x.second] = false;
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int a, b;
cin >> a >> b;
adj[a].push_back(b);
rev[b].push_back(a);
}
for (int i = 1; i <= n; i++) {
caras[i].push_back({0, i});
for (int u : adj[i]) {
merge(u, i);
}
}
for (int i = 0; i < q; i++) {
int t, y;
cin >> t >> y;
for (int j = 0; j < y; j++) {
cin >> bosta[j];
blocked[bosta[j]] = true;
}
if (y > MAXS) {
for (int j = 1; j <= n; j++) {
dp[j] = -1;
}
dp[t] = 0;
for (int v = n; v >= 1; v--) {
for (int u : rev[v]) {
dp[u] = max(dp[u], dp[v] + 1);
}
}
int ans = -1;
for (int j = 1; j <= t; j++) {
if (!blocked[j]) ans = max(ans, dp[j]);
}
cout << ans << '\n';
} else {
int ans = -1;
for (auto x : caras[t]) {
if (!blocked[x.second]) {
ans = x.first;
break;
}
}
cout << ans << '\n';
}
for (int j = 0; j < y; j++) {
blocked[bosta[j]] = false;
}
}
return 0;
}
