#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long
using i64 = long long;
template <class F, class _S>
bool chmin(F &u, const _S &v){
bool flag = false;
if ( u > v ){
u = v; flag |= true;
}
return flag;
}
template <class F, class _S>
bool chmax(F &u, const _S &v){
bool flag = false;
if ( u < v ){
u = v; flag |= true;
}
return flag;
}
const int B = 321;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, q; cin >> n >> m >> q;
vector <vector<int>> G(n);
for ( int i = 1; i <= m; i++ ){
int u, v; cin >> u >> v;
--u, --v;
G[u].pb(v);
}
vector <vector<int>> dp(n, vector <int> (B, -1)), fa(n, vector <int> (B, -1));
for ( int i = 0; i < n; i++ ){
dp[i][0] = 0;
fa[i][0] = i;
}
for ( int u = 0; u < n; u++ ){
auto prev = [&](auto &q){
auto f = q.top();
q.pop();
auto ret = f;
if ( q.empty() ){
ret = {-1, -1};
} else ret = q.top();
q.push(f);
return ret;
};
for ( auto &v: G[u] ){
priority_queue <pair<int,int>> q;
for ( int j = 0; j < B; j++ ){
if ( dp[u][j] != -1 ){
q.push({dp[u][j] + 1, fa[u][j]});
}
}
for ( int j = 0; j < B; j++ ){
int L = dp[v][j], R = fa[v][j];
while ( !q.empty() && q.top().first == -1 ){
q.pop();
}
if ( q.empty() ) break;
if ( fa[v][j] == q.top().second ){
auto [d, p] = prev(q);
if ( chmax(dp[v][j], d) ){
fa[v][j] = p;
auto f = q.top();
q.pop(), q.pop();
q.push(f);
q.push({L, R});
}
} else if ( chmax(dp[v][j], q.top().first) ){
fa[v][j] = q.top().second;
q.pop();
q.push({L, R});
}
}
}
}
vector <int> us(n);
while ( q-- ){
int t, y; cin >> t >> y;
--t;
vector <int> c(y);
for ( auto &x: c ){
cin >> x; --x;
us[x] = true;
}
if ( y + 1 < B ){
int opt = -1;
for ( int j = 0; j < B; j++ ){
if ( dp[t][j] != -1 && !us[fa[t][j]] ){
opt = dp[t][j];
break;
}
}
cout << opt << ln;
} else{
vector <int> dp(n, -1);
for ( int i = 0; i < n; i++ ){
if ( !us[i] ) chmax(dp[i], 0LL);
for ( auto &v: G[i] ){
if ( dp[i] != -1 ){
chmax(dp[v], dp[i] + 1);
}
}
}
cout << dp[t] << ln;
}
for ( auto &x: c ){
us[x] = false;
}
}
cout << '\n';
}
