#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define pb push_back
#define pii pair<int, int>
#define f first
#define s second
#define oo 1000000000
const int b = 320;
vector<vector<int>> ed;
vector<vector<pii>> mx;
vector<int> dist;
vector<int> dp;
vector<bool> busy;
void dfs(int v){
for (auto to : ed[v]){
for (auto x : mx[v]){
dist[x.s] = x.f;
}
for (auto x : mx[to]) {
dist[x.s] = max(dist[x.s], x.f + 1);
}
for (auto& x : mx[v]){
x.f = max(x.f, dist[x.s]); dist[x.s] = 0;
}
for (auto x : mx[to]){
if (dist[x.s] > 0) {
mx[v].pb({x.f+1, x.s}); dist[x.s] = 0;
}
}
}
sort(mx[v].rbegin(), mx[v].rend());
while (mx[v].size() > b) mx[v].pop_back();
if (mx[v].size() < b) mx[v].pb({0, v});
}
void calc(int v){
if (busy[v]) dp[v] = -1;
for (auto to : ed[v]){
if (busy[to]) continue;
dp[v] = max(dp[v], dp[to] + 1);
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m, q; cin >> n >> m >> q;
ed.resize(n+1);
mx.resize(n+1);
dist.resize(n+1);
busy.resize(n+1);
for (int i = 0; i < m; ++i) {
int u, v; cin >> u >> v;
ed[v].pb(u);
}
for (int i = 1; i <= n; ++i) {
dfs(i);
}
for (int i = 0; i < q; ++i) {
int t, y; cin >> t >> y;
vector<int> cur(y);
for (int j = 0; j < y; ++j) {
cin >> cur[j];
busy[cur[j]] = true;
}
if (y < b){
int ans = -1;
for (auto x : mx[t]){
//cout << x.f << " " << x.s << "\n";
if (!busy[x.s]) {
ans = x.f; break;
}
}
cout << ans << "\n";
} else{
dp.assign(n+1, 0);
for (int j = 1; j <= t; ++j) {
calc(j);
}
cout << dp[t] << "\n";
}
for (auto x : cur) busy[x] = false;
}
return 0;
}
