#include <bits/stdc++.h>
using namespace std;
using ull = unsigned long long;
using ll = long long;
using ld = long double;
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
// #define int long long
constexpr int N = 1'000'00, c = 100;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/hash_policy.hpp>
using namespace __gnu_pbds;
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
// http://xorshift.di.unimi.it/splitmix64.c
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
vector<int> g[N];
bool used[N];
vector<pair<int, int>> dsts[N];
void dfs(int v) {
used[v] = true;
vector<pair<int, int>> elems;
elems.emplace_back(0, v);
for (int to : g[v]) {
if (!used[to]) {
dfs(to);
}
for (auto el : dsts[to]) {
elems.emplace_back(el.first + 1, el.second);
}
}
sort(elems.rbegin(), elems.rend());
gp_hash_table<int, null_type, custom_hash> was;
for (auto [d, u] : elems) {
if (dsts[v].size() > c) break;
if (was.find(u) == was.end()) {
dsts[v].emplace_back(d, u);
was.insert(u);
}
}
}
inline void solve() {
int n, m, q;
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int s, e;
cin >> s >> e;
s--;
e--;
g[e].push_back(s);
}
for (int i = 0; i < n; i++) {
if (!used[i]) dfs(i);
}
for (int i = 0; i < q; i++) {
int t, k;
cin >> t >> k;
t--;
if (k > c) {
vector<int> dp(t + 1, -1e9);
vector<bool> can(t + 1, true);
for (int i = 0; i < k; i++) {
int c;
cin >> c;
c--;
if (c > t) continue;
can[c] = false;
}
for (int i = 0; i < t + 1; i++) {
if (can[i]) {
dp[i] = 0;
}
for (int to : g[i]) {
if (dp[to] == -1e9) continue;
dp[i] = max(dp[i], dp[to] + 1);
}
}
cout << (dp.back() == -1e9 ? -1 : dp.back()) << "\n";
continue;
}
gp_hash_table<int, null_type, custom_hash> els;
for (int i = 0; i < k; i++) {
int c;
cin >> c;
c--;
els.insert(c);
}
int ans = -1;
for (auto [d, v] : dsts[t]) {
if (els.find(v) == els.end()) {
ans = d;
break;
}
}
cout << ans << "\n";
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
