#include <iostream>
#include <vector>
using namespace std;
#define ii pair <int, int>
#define fi first
#define se second
const int N = 1e5 + 10;
const int BlockSize = 320;
int n, m, k;
int x, y;
vector <int> g[N];
vector <ii> mx[N];
struct query {
int st, num;
vector <int> v;
} q;
bool used[N];
vector <ii> combine(const vector <ii> &A, const vector <ii> &B) {
vector <ii> res;
res.clear();
int i = 0, j = 0;
while (i < A.size() || j < B.size()) {
if (res.size() == BlockSize) break;
if (j == B.size() || (i < A.size() && A[i].fi + 1 > B[j].fi)) {
if (!used[A[i].se]) {
res.push_back(ii(A[i].fi + 1, A[i].se));
used[A[i].se] = true;
}
++i;
} else {
if (!used[B[j].se]) {
res.push_back(B[j]);
used[B[j].se] = true;
}
++j;
}
}
for (ii z: res) used[z.se] = false;
return res;
}
vector <int> need;
bool tham[N];
int curans[N];
void solve(int s) {
tham[s] = true;
need.push_back(s);
curans[s] = 0;
for (int z: g[s]) {
if (!tham[z]) solve(z);
curans[s] = max(curans[s], curans[z] + 1);
}
if (curans[s] == 0 && used[s]) curans[s] = -1e9;
}
int main() {
cin.tie(0); cout.tie(0);
ios_base::sync_with_stdio(false);
cin >> n >> m >> k;
while (m--) {
cin >> x >> y;
g[y].push_back(x);
}
for (int i = 1; i <= n; ++i) {
mx[i].push_back(ii(0, i));
for (int z: g[i]) {
mx[i] = combine(mx[z], mx[i]);
}
}
while (k--) {
cin >> q.st >> q.num;
q.v.clear();
q.v.resize(q.num);
for (int &z: q.v) {
cin >> z;
used[z] = true;
}
if (q.num < BlockSize) {
int i = 0;
while (i < mx[q.st].size() && used[mx[q.st][i].se]) ++i;
if (i < mx[q.st].size()) cout << mx[q.st][i].fi << "\n";
else cout << "-1\n";
} else {
solve(q.st);
if (curans[q.st] < 0) curans[q.st] = -1;
cout << curans[q.st] << "\n";
for (int z: need) tham[z] = false;
need.clear();
}
for (int z: q.v) used[z] = false;
}
return 0;
}
