#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) (x).begin(), (x).end()
const int N = 1e5 + 7, B = 317;
int n, m, q;
vector<int> adj[N];
vector<array<int, 2>> bst[N];
bool used[N];
int dp[N];
int main() {
cin.tie(0)->sync_with_stdio(false);
cin >> n >> m >> q;
for (int i = 1; i <= m; i++) {
int u, v;
cin >> u >> v;
adj[u].push_back(v);
}
for (int i = 1; i <= n; i++) {
bst[i].push_back({0, i});
}
for (int i = 1; i <= n; i++) {
for (auto &[d, x] : bst[i])
d++;
for (int j : adj[i]) {
vector<array<int, 2>> c;
auto add = [&](array<int, 2> &a) {
if (!used[a[1]]) {
c.push_back(a);
used[a[1]] = 1;
}
};
int l = 0, r = 0;
while (c.size() < B) {
if (l == bst[i].size() && r == bst[j].size())
break;
if (r == bst[j].size() || (l < bst[i].size() && bst[i][l][0] > bst[j][r][0]))
add(bst[i][l++]);
else
add(bst[j][r++]);
}
for (auto &[d, x] : c)
used[x] = 0;
bst[j] = c;
}
for (auto &[d, x] : bst[i])
d--;
}
while (q--) {
int t, k;
cin >> t >> k;
vector<int> ban(k);
for (int &i : ban) {
cin >> i;
used[i] = 1;
}
if (k < B) {
int ans = -1;
for (auto &[d, x] : bst[t]) {
if (!used[x]) {
ans = d;
break;
}
}
cout << ans << '\n';
}
else {
memset(dp, -1, sizeof(dp));
dp[t] = 0;
int ans = -1;
for (int i = t; i >= 1; i--) {
for (int j : adj[i]) {
if (dp[j] != -1)
dp[i] = max(dp[i], dp[j] + 1);
}
if (!used[i])
ans = max(ans, dp[i]);
}
cout << ans << '\n';
}
for (int i : ban)
used[i] = 0;
}
return 0;
}
