#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int B = 447, inf = 1e9 + 5;
bool chmax(int &a, const int &b) {
return a < b ? a = b, true : false;
}
void solve() {
int n, m, q; cin >> n >> m >> q;
vector<vector<int>> radj(n);
for(int i = 0; i < m; i++) {
int u, v; cin >> u >> v;
u--, v--;
radj[v].push_back(u);
}
vector<vector< array<int, 2> >> sql(n);
for(int i = 0; i < n; i++) {
int sz = radj[i].size();
vector<int> ptr(sz);
for(int it = 0; it < B; it++) {
int mx = -1, v = -1;
for(int j = 0; j < sz; j++) {
int from = radj[i][j];
if(ptr[j] < (int)sql[from].size()) {
if( chmax(mx, sql[from][ptr[j]][0]) ) {
v = sql[from][ptr[j]][1];
}
}
}
if(v == -1) break;
for(int j = 0; j < sz; j++) {
int from = radj[i][j];
if(ptr[j] < (int)sql[from].size() && v == sql[from][ptr[j]][1]) {
sql[i].push_back({mx + 1, v});
ptr[j]++;
break;
}
}
}
if(sql[i].size() < B) sql[i].push_back({0, i});
sort(sql[i].begin(), sql[i].end(), greater<>());
}
vector<int> is(n);
while(q--) {
int T, Y; cin >> T >> Y;
T--;
vector<int> C(Y);
for(auto &x : C) {
cin >> x;
is[--x] = 1;
}
if(Y <= B) {
int mx = -1;
for(auto [d, u] : sql[T]) {
if(!is[u]) {
mx = d;
break;
}
}
cout << mx << '\n';
} else {
vector<int> dp(n);
for(auto &x : C) dp[x] = -inf;
for(int i = 0; i < n; i++) {
for(auto from : radj[i]) {
if(dp[from] != -inf) chmax(dp[i], dp[from] + 1);
}
}
cout << (dp[T] == -inf ? -1 : dp[T]) << '\n';
}
for(auto &x : C) is[x] = 0;
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
