#include<bits/stdc++.h>
// #define int long long
#define fi first
#define se second
#define pb push_back
#define ii pair<int, int>
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()
using namespace std;
const int N=1e5+5, mod = 1e9+7, block = 100;
int n, m, q, vis[N], dp[N];
bool del[N];
vector<int> lst, adj[N];
vector<ii> rnk[N];
void clr(priority_queue<ii>& pq) { while(sz(pq)) pq.pop(); }
void pre() {
priority_queue<ii> pq;
for (int i=1; i<=n; i++) {
pq.push({0, i});
for (int u: adj[i]) {
for (auto [v, d]: rnk[u]) pq.push({d+1, v});
}
while(sz(rnk[i])<block && sz(pq)) {
auto [d, u] = pq.top(); pq.pop();
if(vis[u]!=i) {
vis[u] = i;
rnk[i].pb({u, d});
}
}
clr(pq);
}
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
for (int i=1; i<=m; i++) {
int u, v; cin >> u >> v;
adj[v].pb(u);
}
pre();
while(q--) {
int t, y; cin >> t >> y;
for (int i=1; i<=y; i++) {
int tmp; cin >> tmp;
lst.pb(tmp); del[tmp] = 1;
}
if(y>=block) {
for (int i=1; i<=t; i++) {
if(del[i]) dp[i] = -1;
else dp[i] = 0;
for (int u: adj[i]) {
if(dp[u]!=-1) dp[i] = max(dp[i], dp[u]+1);
}
}
cout << dp[t] << '\n';
} else {
bool b = 1;
for (auto [u, d]: rnk[t]) {
if(!del[u]) {
cout << d << '\n';
b = 0; break;
}
}
if(b) cout << -1 << '\n';
}
for (auto it: lst) del[it] = 0;
lst.clear();
}
}
