//Challenge: Accepted
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#define ll long long
#define maxn 100005
#define pii pair<int, int>
#define ff first
#define ss second
using namespace std;
const int siz = 140;
vector<int> adj[maxn], from[maxn];
vector<pii> pnt[maxn], tmp;
inline bool cmp (pii a, pii b) {
return a.ss > b.ss;
}
int dp[maxn];
bool part[maxn], found[maxn];
void getdp(int n, int id) {
for (int i = 1;i <= id;i++) dp[i] = 0;
for (int i = 1;i <= id;i++) {
for (int v:adj[i]) {
dp[v] = max(dp[v], (dp[i] == 0 ? (part[i] ? -1 : 0) : dp[i]) + 1);
}
}
}
vector<pii> merge(vector<pii> a, vector<pii> b) {
vector<pii> ret;
for (auto &i:b) i.ss++;
int n = a.size(), m = b.size(), ind = 0;
for (int i = 0;i < n;i++) {
while (ind < m && b[ind].ss > a[i].ss) {
if (!found[b[ind].ff]) {
found[b[ind].ff] = 1;
ret.push_back(b[ind]);
}
ind++;
if (ret.size() > siz) break;
}
if (!found[a[i].ff]) {
found[a[i].ff] = 1;
ret.push_back(a[i]);
}
if (ret.size() > siz) break;
}
while (ind < m) {
if (!found[b[ind].ff]) {
found[b[ind].ff] = 1;
ret.push_back(b[ind]);
}
ind++;
if (ret.size() > siz) break;
}
for (auto i:ret) found[i.ff] = 0;
while (ret.size() > siz) ret.pop_back();
return ret;
}
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
for (int i = 0;i < m;i++) {
int a, b;
cin >> a >> b;
adj[a].push_back(b);
from[b].push_back(a);
}
for (int i = 1;i <= n;i++) {
pnt[i].push_back(make_pair(i, 0));
for (int v:from[i]) {
pnt[i] = merge(pnt[i], pnt[v]);
}
}
getdp(n, n);
while (q--) {
int ind, yi;
cin >> ind >> yi;
vector<int> val;
for (int i = 0;i < yi;i++) {
int x;
cin >> x;
part[x] = 1;
val.push_back(x);
}
if (yi >= siz) {
getdp(n, ind);
if (part[ind] && dp[ind] == 0) cout << -1 << "\n";
else cout << dp[ind] << "\n";
} else {
int ans = -1;
for (auto v:pnt[ind]) {
if (!part[v.ff]) ans = max(ans, v.ss);
}
cout << ans << "\n";
}
for (int i:val) part[i] = 0;
}
}
/*
5 6 3
1 2
2 4
3 4
1 3
3 5
4 5
4 1 1
5 2 2 3
2 3 1 4 5
*/
