#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
#define t_test int t;cin >> t;while(t--)
const ll mod = 1e9 + 7;
const ll INF = 1e17;
const ll B = 100;
const ll N = 1e5 + 5;
ll n, m, q;
ll a[N], dx[N], dp[N];
vector<ll> r_g[N];
vector<pa> dist[N];
void slove2(ll &t, ll &y) {
FORD(i, t, 1) {
dp[i] = -1;
}
dp[t] = 0;
FORD(i, t, 1) {
if(dp[i] == -1) continue;
for(auto v : r_g[i]) {
dp[v] = max(dp[i] + 1, dp[v]);
}
}
ll ans = -1;
FOR(i, 1, t) {
if(!dx[i]) {
ans = max(ans, dp[i]);
}
}
cout << ans << '\n';
FOR(i, 1, y) {
dx[a[i]] = 0;
}
}
void hbmt() {
// inp
cin >> n >> m >> q;
FOR(i, 1, m) {
ll u, v;
cin >> u >> v;
r_g[v].push_back(u);
}
// pre
FOR(i, 1, n) {
vector<pa> vt;
for(auto v : r_g[i]) {
for(auto e : dist[v]) {
vt.push_back({e.fi + 1, e.se});
}
vt.push_back({1, v});
}
vt.push_back({0, i});
sort(vt.begin(), vt.end(), greater<pa>());
while(vt.size() > B) {
vt.pop_back();
}
ll pre = 0;
for(auto v : vt) {
if(pre == v.se) continue;
pre = v.se;
dist[i].push_back(v);
}
}
ll t, y;
FOR(i, 1, q) {
cin >> t >> y;
FOR(j, 1, y) {
cin >> a[j];
dx[a[j]] = 1;
}
if(y >= B) {
slove2(t, y);
continue;
}
bool ok = false;
for(auto e : dist[t]) {
if(dx[e.se] == 0) {
ok = true;
cout << e.fi << '\n';
break;
}
}
if(!ok) cout << -1 << '\n';
FOR(j, 1, y) {
dx[a[j]] = 0;
}
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
if(fopen("hbmt.inp", "r")) {
freopen("hbmt.inp", "r", stdin);
freopen("hbmt.out", "w", stdout);
}
// t_test
hbmt();
return 0;
}
