#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int SQ = 100;
const int mxN = 1e5+10;
vector<int> adj[mxN];
int main()
{
ios_base::sync_with_stdio(0);
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[b].push_back(a);
}
vector<vector<array<int, 2>>> paths(n+1);
vector<int> from(n+1, -1);
for(int i = 1; i <= n; i++) {
paths[i].push_back({0, i});
vector<int> from_idx;
for(auto it : adj[i]) {
for(auto [dist, idx] : paths[it]) {
if(from[idx] == -1) {
from_idx.push_back(idx);
from[idx] = dist+1;
}
else {
from[idx] = max(from[idx], dist+1);
}
}
}
for(int j : from_idx) paths[i].push_back({from[j], j});
sort(paths[i].rbegin(), paths[i].rend());
while(paths[i].size() > SQ) paths[i].pop_back();
for(int j : from_idx) from[j] = -1;
}
vector<bool> blocked(n+1);
while(q--) {
int t, y;
cin >> t >> y;
vector<int> now(y);
for(int i = 0; i < y; i++) {
cin >> now[i];
blocked[now[i]] = true;
}
int ans = -1;
if(y >= SQ) {
vector<int> dp(t+1, -1);
dp[t] = 0;
for(int i = t; i >= 0; i--) {
if(dp[i] == -1) continue;
if(!blocked[i]) ans = max(ans, dp[i]);
for(auto it : adj[i]) {
dp[it] = max(dp[it], dp[i]+1);
}
}
}
else {
for(auto [dist, idx] : paths[t]) {
if(blocked[idx]) continue;
ans = dist;
break;
}
}
cout << ans << '\n';
for(auto it : now) blocked[it] = false;
}
return 0;
}
