#include <bits/stdc++.h>
#define fi first
#define se second
#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 coutE(x) {cout << x << '\n'; return;}
#define pb push_back
#define pf push_front
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define bs binary_search
#define ub upper_bound
#define lb lower_bound
#define endl '\n'
#define db long double
#define ll long long
#define ii pair<int, int>
#define vi vector<int>
#define vii vector<ii>
#define int long long
using namespace std;
void file(string s){
if (s.empty()) return;
freopen((s + ".inp").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
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;
}
mt19937_64 rng(time(0));
const int N = 1e6 + 5;
const int B = 120;
const int MOD = 1e9 + 7; //998244353;
const int INF = 1e9;
const long long LINF = 1e18;
const int dx[] = {1, 0, 0, -1};
const int dy[] = {0, 1, -1, 0};
int n, m, q, busy_pussy[N];
vi g[N];
bool seen[N], busy[N];
int dp[N];
set<ii, greater<>> st[N];
void dfs(int u, bool mark){
seen[u] = 1;
dp[u] = busy[u] ? -INF : 0;
if (mark) st[u].insert({0, u});
for (int v: g[u]){
if (!seen[v]) dfs(v, mark);
maximize(dp[u], dp[v] + 1);
if (!mark) continue;
for (ii p: st[v]){
++p.fi;
if (sz(st[u]) < B) st[u].insert(p);
else{
if (st[u].begin()->fi >= p.fi) break;
st[u].erase(st[u].begin());
st[u].insert(p);
}
}
}
}
void solve(){
cin >> n >> m >> q;
rep(i, m){
int u, v; cin >> u >> v;
g[v].pb(u);
}
ForD(i, n, 1) if (!seen[i])
dfs(i, 1);
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{
memset(seen, 0, sizeof seen);
dfs(u, 0);
cout << (dp[u] >= 0 ? dp[u] : -1) << '\n';
}
rep(i, k) busy[busy_pussy[i]] = 0;
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
file("");
int T = 1;
//cin >> T;
while (T--) solve();
return 0;
}
