#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;
vector<int> g[N];
bool used[N];
map<int, int> elems[N];
set<pair<int, int>> dsts[N];
void dfs(int v) {
used[v] = true;
elems[v][v] = 0;
dsts[v].emplace(0, v);
for (int to : g[v]) {
if (!used[to]) {
dfs(to);
}
for (auto [x, _dst] : elems[to]) {
int dst = _dst + 1;
if (elems[v].count(x)) {
dsts[v].erase({elems[v][x], x});
elems[v][x] = max(elems[v][x], dst);
dsts[v].insert({elems[v][x], x});
continue;
}
if (elems[v].size() <= c) {
elems[v][x] = dst;
dsts[v].insert({elems[v][x], x});
} else if (dst > dsts[v].begin()->first) {
auto [_, u] = *dsts[v].begin();
elems[v].erase(u);
dsts[v].erase(dsts[v].begin());
elems[v][x] = dst;
dsts[v].insert({elems[v][x], x});
}
}
}
}
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;
}
set<int> els;
for (int i = 0; i < k; i++) {
int c;
cin >> c;
c--;
els.insert(c);
}
int ans = -1;
for (auto [v, d] : elems[t]) {
if (!els.count(v)) {
ans = max(ans, d);
}
}
cout << ans << "\n";
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
