#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define pb push_back
#define all(a) a.begin(), a.end()
#define endl "\n"
void printVector(vector<int> a){
for (auto x: a) cout << x << " ";
cout << endl;
}
void solve(){
int n, m, q; cin >> n >> m >> q;
vector<vector<int>> graph(n+1);
FOR(i,0,m){
int s, e; cin >> s >> e;
graph[e].pb(s);
}
vector<vector<pair<int, int>>> path_sizes(n+1);
vector<int> from(n+1, -1);
for (int i = 1; i <= n; ++i){
path_sizes[i].pb({0, i});
vector<int> ind;
for (auto x: graph[i]){
for (auto [dist, node]: path_sizes[x]){
if (from[node] == -1){
ind.pb(node);
from[node] = dist+1;
}else{
from[node] = max(from[node], dist+1);
}
}
}
for (auto x: ind){
path_sizes[i].pb({from[x], x});
}
sort(all(path_sizes[i]));
reverse(all(path_sizes[i]));
while (path_sizes[i].size() > 100){
path_sizes[i].pop_back();
}
for (auto x: ind) from[x] = -1;
}
vector<int> blocked(n+1);
while (q--){
int t, y; cin >> t >> y;
vector<int> c(y);
FOR(i,0,y){
cin >> c[i];
blocked[c[i]] = 1;
}
int ans = -1;
if (y >= 100){
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 x: graph[i]) dp[x] = max(dp[x], dp[i]+1);
}
}else{
for (auto [dist, node]: path_sizes[t]){
if (!blocked[node]){
ans = dist;
break;
}
}
}
cout << ans << endl;
for (auto x: c) blocked[x] = 0;
}
}
int32_t main(){
ios::sync_with_stdio(false);cin.tie(nullptr);
int t = 1;// cin >> t;
while (t--) solve();
}
