#include <bits/stdc++.h>
#define For(i, a, b) for (int i = (a); i <= (b); ++i)
#define ForD(i, a, b) for (int i = (a); i >= (b); --i)
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repD(i, n) for (int i = (n) - 1; i >= 0; --i)
#define pb push_back
#define sz(x) (int)x.size()
#define endl '\n'
#define fi first
#define se second
#define ii pair<int, int>
#define vi vector<int>
using namespace std;
template <class X, class Y>
bool minimize(X &x, Y y){
if (x > y){
x = y;
return 1;
}
return 0;
}
template <class X, class Y>
bool maximize(X &x, Y y){
if (x < y){
x = y;
return 1;
}
return 0;
}
const int N = 1e5 + 5;
const int B = 100;
const int INF = 1e9;
int n, m, q, busy_pussy[N];
vi g[N];
bool busy[N];
int dp[N];
set<ii, greater<>> st[N];
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
rep(i, m){
int u, v; cin >> u >> v;
g[v].pb(u);
}
For(i, 1, n){
st[i].insert({0, i});
for (int j: g[i]){
for (ii p: st[j]){
++p.fi;
if (sz(st[i]) < B) st[i].insert(p);
else{
if (st[i].rbegin()->fi >= p.fi) break;
st[i].erase(*st[i].rbegin());
st[i].insert(p);
}
}
}
}
while (q--){
int u, k; cin >> u >> k;
int cnt = 0;
rep(i, k){
cin >> busy_pussy[i];
if (busy_pussy[i] > u) continue;
++cnt;
busy[busy_pussy[i]] = 1;
}
if (cnt < sz(st[u])){
bool ok = 0;
for (auto [d, v]: st[u]) if (!busy[v]){
cout << d << '\n';
ok = 1;
break;
}
if (!ok) cout << -1 << '\n';
}
else{
For(i, 1, u){
dp[i] = busy[i] ? -INF : 0;
for (int j: g[i]){
maximize(dp[i], dp[j] + 1);
}
}
cout << (dp[u] >= 0 ? dp[u] : -1) << '\n';
}
rep(i, k) busy[busy_pussy[i]] = 0;
}
return 0;
}
