#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pll;
#define all(x) (x).begin(),(x).end()
#define X first
#define Y second
#define sep ' '
#define endl '\n'
#define debug(x) cerr << #x << ": " << x << endl;
const ll MAXN = 1e5 + 10;
const ll SQ = 350;
vector<pll> vec[MAXN];
vector<int> adj[MAXN];
int dp[MAXN], n, m, q;
bool vis[MAXN];
inline vector<pll> merge(vector<pll> A, vector<pll> B) {
vector<pll> ans;
int sz_a = A.size(), sz_b = B.size(), pa = 0, pb = 0;
while ((pa < sz_a || pb < sz_b) && int(ans.size()) < SQ) {
int v, d;
if (pa == sz_a || (pb < sz_b && A[pa].Y < B[pb].Y)) tie(v, d) = B[pb++];
else tie(v, d) = A[pa++];
if (vis[v]) continue;
ans.push_back({v, d});
vis[v] = true;
}
for (auto [v, _] : ans) vis[v] = false;
return ans;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int u, v;
cin >> v >> u;
adj[u].push_back(v);
}
for (int v = 1; v <= n; v++) {
vec[v].push_back({v, 0});
for (int u : adj[v]) {
vector<pll> T = vec[u];
for (auto& x : T) x.Y++;
vec[v] = merge(vec[v], T);
}
}
while (q--) {
int v, m;
cin >> v >> m;
vector<int> tmp;
for (int i = 0; i < m; i++) {
int v;
cin >> v;
vis[v] = true;
tmp.push_back(v);
}
int tans = -1;
for (auto [v, d] : vec[v]) {
if (!vis[v]) {
tans = d;
break;
}
}
if (tans == -1 && ll(vec[v].size()) == SQ) {
for (int i = 1; i <= v; i++) {
dp[v] = (vis[v] ? -MAXN : 0);
for (int u : adj[v])
dp[v] = max(dp[v], dp[u] + 1);
}
tans = max(tans, dp[v]);
}
cout << tans << endl;
for (int e : tmp) vis[e] = false;
}
return 0;
}
