#include <bits/stdc++.h>
using namespace std;
void maxi(int &x, int y) {
if(x < y) x = y;
}
const int C = 100;
bool vis[100005];
void merge(vector<pair<int, int>> &a, const vector<pair<int, int>> &b) {
vector<pair<int, int>> c;
int n = (int)a.size(), m = (int)b.size();
for(int i = 0, j = 0; i < n || j < m;) {
if((int)c.size() == C) break;
if(i < n && vis[a[i].second]) { ++i; continue; }
if(j < m && vis[b[j].second]) { ++j; continue; }
if(j == m || (i < n && a[i].first > b[j].first+1)) {
c.push_back(a[i]);
vis[a[i++].second] = 1;
} else {
c.push_back({b[j].first+1, b[j].second});
vis[b[j++].second] = 1;
}
}
for(const auto &p : c) vis[p.second] = 0;
a = c;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
vector<vector<int>> g(n+1);
vector<vector<int>> r(n+1);
for(int i = 1; i <= m; ++i) {
int u, v; cin >> u >> v;
g[u].push_back(v);
r[v].push_back(u);
}
vector<int> dst(n+1);
vector<vector<pair<int, int>>> list(n+1);
for(int i = 1; i <= n; ++i) {
for(int x : r[i]) {
merge(list[i], list[x]);
}
if((int)list[i].size() < C) list[i].push_back({0, i});
}
vector<bool> blocked(n+1);
vector<int> dp(n+1);
blocked[0] = 1;
while(q--) {
int t, x; cin >> t >> x;
vector<int> v(x);
for(int i = 0; i < x; ++i) {
cin >> v[i];
blocked[v[i]] = 1;
}
int ans = -1;
if(x < C) {
for(pair<int, int> p : list[t]) {
if(!blocked[p.second]) {
ans = p.first;
break;
}
}
} else {
for(int i = 1; i <= t; ++i) {
dp[i] = -1e6;
if(!blocked[i]) {
dp[i] = 0;
}
for(int x : r[i]) {
maxi(dp[i], dp[x]+1);
}
}
ans = dp[t];
}
if(ans < 0) ans = -1;
cout << ans << '\n';
for(int i : v) blocked[i] = 0;
}
}
