#include <bits/stdc++.h>
#define int long long
using namespace std;
using vi = vector<int>;
using pi = pair<int,int>;
using ll = long long;
const int B = 100;
const int MAX_N = 1e5 + 5;
vector<vi>adjL(MAX_N);
vector<vector<pi>>paths(MAX_N);
void solve() {
int n, m, q;
cin >> n >> m >> q;
for(int i=0; i<m; ++i) {
int x, y;
cin >> x >> y;
adjL[y].push_back(x);
}
for(int i=1; i<=n; ++i) {
priority_queue<pi>pq;
pq.push({0, i});
set<int> added;
for(int adj: adjL[i]) {
for(pi p: paths[adj]) pq.push({p.first+1, p.second});
}
while(!pq.empty() && paths[i].size() < B) {
pi cur = pq.top();
pq.pop();
auto it = find(added.begin(), added.end(), cur.second);
if(it == added.end()) {
paths[i].push_back(cur);
added.insert(cur.second);
}
}
}
vi blk(n+1, -1);
for(int i=0; i<q; ++i) {
int t, num;
cin >> t >> num;
if(num >= B) {
vi dp(t+1, 0);
for(int j=t; j>=1; --j) {
if(!dp[j] && j != t) continue;
for(int adj: adjL[j]) {
dp[adj] = max(dp[adj], dp[j] + 1);
}
}
for(int j=0; j<num; ++j) {
int tmp;
cin >> tmp;
blk[tmp] = i;
}
int ans = -1;
for(int j=1; j<=t; ++j) {
if(blk[j] != i && dp[j]) {
ans = max(ans, dp[j]);
}
}
if(ans == -1 && blk[t] != i) ans = 0;
cout << ans << endl;
} else {
int ans = -1;
for(int j=0; j<num; ++j) {
int tmp;
cin >> tmp;
blk[tmp] = i;
}
for(int j=0; j<paths[t].size(); ++j) {
int tmp = paths[t][j].second;
if(blk[tmp] != i) {
ans = paths[t][j].first;
break;
}
}
cout << ans << endl;
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int t = 1;
while(t--) solve();
return 0;
}
