#include <algorithm>
#include <cassert>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
using ll = long long;
using vl = vector<ll>;
istream &operator>>(istream &os, vl &a) {
for (auto &x: a) cin >> x;
return os;
}
constexpr int N = 200200;
constexpr int B = 150;
vector<int> g[N], ig[N];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, q;
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int s, e;
cin >> s >> e;
g[s].push_back(e);
ig[e].push_back(s);
}
std::vector<std::vector<pair<int, int> > > least(n + 1, std::vector<pair<int, int> >());
std::vector<bool> used(n + 1, false);
least[1] = {{0, 1}};
for (int i = 2; i <= n; i++) {
vector<int> free;
std::vector<int> can;
std::vector<int> sz;
for (const auto &d: ig[i]) {
can.push_back(d);
sz.push_back(least[d].size());
}
std::vector<int> ind(sz.size(), 0);
for (int j = 0; j < B; j++) {
int mx = -1;
int where = -1;
for (int id = 0; id < sz.size(); id++) {
while (ind[id] < sz[id] && used[least[can[id]][ind[id]].second]) {
ind[id]++;
}
}
for (int id = 0; id < sz.size(); id++) {
if (ind[id] < sz[id] && least[can[id]][ind[id]].first > mx) {
mx = least[can[id]][ind[id]].first;
where = least[can[id]][ind[id]].second;
}
}
if (where == -1) {
break;
} else {
used[where] = true;
free.push_back(where);
ind[where]++;
least[i].emplace_back(mx + 1, where);
}
}
if (least[i].size() < B) {
least[i].emplace_back(0, i);
}
for (auto &d: free) used[d] = false;
}
for (int i = 0; i < q; i++) {
int t, y;
cin >> t >> y;
vector<int> blocked(y);
std::set<int> bl;
for (int j = 0; j < y; j++) {
cin >> blocked[j];
bl.insert(blocked[j]);
}
if (y >= B) {
std::vector<int> dp(n + 1, -1);
dp[t] = 0;
for (int j = t; j >= 1; j--) {
if (dp[j] == -1) continue;;
for (const auto &d: ig[j]) {
dp[d] = max(dp[d], dp[j] + 1);
}
}
int value = -1;
for (int g = 1; g <= t; g++) {
if (!bl.contains(g)) value = max(value, dp[g]);
}
std::cout << value << "\n";
} else {
int value = -1;
for (const auto &d: least[t]) {
if (!bl.contains(d.second)) value = max(value, d.first);
}
std::cout << value << "\n";
}
}
}
