#include "bits/stdc++.h"
// @JASPER'S BOILERPLATE
using namespace std;
using ll = long long;
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FORD(i, a, b) for(int i = a; i >= b; i--)
#define REP(i, b) for(int i = 0; i < b; i++)
#define PER(i, b) for(int i = b - 1; i >= 0; i--)
#define fi first
#define se second
#ifdef JASPER
#include "debug.h"
#else
#define debug(...) 166
#endif
using pii = pair < int, int >;
const int INF = 1e9;
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int BLOCK = 250;
vector <int> adj[N];
vector <pii> opt[N];
int n, m, q;
int dis[N], src[N];
void run_case() {
cin >> n >> m >> q;
for (int i = 1; i <= m; ++i) {
int u, v; cin >> u >> v;
adj[v].push_back(u);
}
vector <int> best;
for (int i = 1; i <= n; ++i) {
vector <int> current;
for (int u : adj[i]) {
for (auto v : opt[u]) {
if (src[v.second] == i) {
dis[v.second] = max(dis[v.second], v.first + 1);
}
else {
src[v.second] = i;
dis[v.second] = v.first + 1;
current.push_back(v.second);
}
}
}
opt[i].push_back({0, i});
for (int j : current)
opt[i].push_back({dis[j], j});
sort(opt[i].begin(), opt[i].end(), greater <pii>());
while ((int) opt[i].size() > BLOCK) opt[i].pop_back();
}
vector <bool> busy(n + 2, 0);
while (q--) {
int x, c;
cin >> x >> c;
vector <int> b;
for (int i = 1; i <= c; ++i) {
int y; cin >> y;
b.push_back(y);
busy[y] = 1;
}
// Apply brute O(n) for x <= sqrt(n) times of total complexity nsqrt(n)
if (c >= BLOCK) {
vector <int> dp(n + 2, -INF);
for (int i = 1; i <= x; ++i) {
if (!busy[i]) dp[i] = 0;
for (int j : adj[i])
dp[i] = max(dp[i], dp[j] + 1);
}
dp[x] = max(dp[x], -1);
cout << dp[x] << "\n";
}
else {
int ans = -1;
for (pii v : opt[x])
if (!busy[v.second])
ans = max(ans, v.first);
cout << ans << "\n";
}
for (int i : b) busy[i] = 0;
}
}
signed main() {
cin.tie(0) -> sync_with_stdio(0);
int Test = 1;
//cin >> Test;
for (int test = 1; test <= Test; test++){
run_case();
}
}
