#include <bits/stdc++.h>
using namespace std;
#define FastIO ios_base::sync_with_stdio(0);cin.tie(nullptr);
#define MULTEST int t;cin >> t;while (t--) solve();
#define rf(__abc__) freopen(__abc__".inp","r",stdin);freopen(__abc__".out","w",stdout);
const int mod = 1e9 + 7;
long long pw(long long x,long long y) {
if (y == 0) return 1;
if (y % 2 == 0) {
long long a = pw(x,y/2);
return a*a%mod;
} else {
long long a = pw(x,y - 1);
return a*x%mod;
}
}
int add(int x,int y) {
x += y;
if (x >= mod) x -= mod;
return x;
}
int subtract(int x,int y) {
x -= y;
if (x < 0) x += mod;
return x;
}
int mul(long long x,int y) {
x *= y;
if (x >= mod) x %= mod;
return x;
}
///Code goes here
int n,m,q;
vector <int> adj[200009];
bool busy[100009],visited[100009];
int dp[100009];
int dfs(int node) {
if (visited[node]) return dp[node];
visited[node] = 1;
dp[node] = (busy[node] ? -1e9 : 0);
for (auto x : adj[node]) {
dp[node] = max(dp[node],dfs(x) + 1);
}
return dp[node];
}
int main() {
//rf("");
FastIO
//MULTEST
cin >> n >> m >> q;
for (int i = 1;i <= m;i++) {
int u,v;cin >> u >> v;
adj[v].push_back(u);
}
while (q--) {
int root,num;cin >> root >> num;
vector <int> record(num + 1);
for (int i = 1;i <= num;i++) {
cin >> record[i];
busy[record[i]] = 1;
}
for (int i = 1;i <= n;i++) visited[i] = dp[i] = 0;
int d = dfs(root);
cout << (d < 0 ? -1 : d) << '\n';
for (int i = 1;i <= num;i++) busy[record[i]] = 0;
}
return 0;
}
