#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF = 1e9 + 7;
const int SQRT = 300;
// bitarooo
int N, M, Q;
signed main() {
cin.tie(0); ios::sync_with_stdio(false);
cin >> N >> M >> Q;
vector<vector<int>> adj(N); // reversed
for(int i = 0; i < M; i++) {
int a, b;
cin >> a >> b;
a--; b--;
adj[b].push_back(a); // topo sorted alr
}
vector<vector<pair<int,int>>> dp(N);
vector<unordered_map<int, int>> victor(N);
for(int v = 0; v < N; v++) {
dp[v].emplace_back(0, v);
for(int &u: adj[v]) {
for(auto &[dist, start]: dp[u]) { // MsqrtN
victor[v][start] = max(victor[start][v], dist + 1);
}
}
for(auto &[start, dist]: victor[v]) {
dp[v].emplace_back(dist, start);
}
sort(dp[v].begin(), dp[v].end());
reverse(dp[v].begin(), dp[v].end());
while(dp[v].size() > SQRT) dp[v].pop_back();
}
for(int i = 0; i < Q; i++) {
int t, y;
cin >> t >> y;
t--;
unordered_set<int> cant;
for(int j = 0; j < y; j++) {
int x;
cin >> x;
x--;
cant.insert(x);
}
if (y < SQRT) {
bool yes = false;
for(int k = 0; k < dp[t].size(); k++) {
if (cant.find(dp[t][k].second) == cant.end()) {
yes = true;
cout << dp[t][k].first << endl;
break;
}
}
if (!yes) cout << -1 << endl;
} else {
vector<int> dp2(N, -INF);
for(int v = 0; v <= t; v++) {
if (cant.find(v) == cant.end()) dp2[v] = 0;
for(int &u: adj[v]) {
dp2[v] = max(dp2[v], dp2[u] + 1);
}
}
if (dp2[t] >= 0) cout << dp2[t] << endl;
else cout << -1;
}
}
}
