#include <bits/stdc++.h>
#define fileIO(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);}
#define SPEED ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define epl emplace
#define pb push_back
#define eb emplace_back
#define EL cout << '\n'
#define dbg(x) cout << #x << " = " << (x) << ' '
#define dbgp(x) cout << #x << " = (" << (x.fi) << ", " << (x.se) << ") "
#define fi first
#define se second
#define mp make_pair
#define sqr(x) (x) * (x)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define lwb lower_bound
#define upb upper_bound
#define ctz __builtin_ctzll
#define pct __builtin_popcountll
using namespace std;
typedef long long ll;
typedef long double ldb;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;
typedef pair<int, int> pii;
typedef pair<ldb, ldb> pld;
typedef pair<double, double> pdd;
template<class T1, class T2> bool minimize(T1 &a, T2 b){return a > b ? a = b, true : false;}
template<class T1, class T2> bool maximize(T1 &a, T2 b){return a < b ? a = b, true : false;}
const int N = 4e5 + 3, Bz = 317;
int n, m, qsn, d[N], who[N];
bool busy[N], seen[N];
vector<int> adj[N], radj[N];
vector<pii> bestd[N];
vector<pii> mergevector(vector<pii> &v1, vector<pii> &v2){
vector<pii> V; vector<int> A;
int p1 = 0, p2 = 0;
while((p1 < v1.size() || p2 < v2.size()) && V.size() <= Bz){
int val1 = -100000, val2 = -100000;
if(p1 < v1.size()) val1 = v1[p1].fi;
if(p2 < v2.size()) val2 = v2[p2].fi + 1;
if(val1 > val2){
V.eb(val1, v1[p1].se);
seen[v1[p1].se] = 1; A.pb(v1[p1].se);
p1++;
}
else{
V.eb(val2, v2[p2].se);
seen[v2[p2].se] = 1; A.pb(v2[p2].se);
p2++;
}
while(p1 < v1.size() && seen[v1[p1].se]) p1++;
while(p2 < v2.size() && seen[v2[p2].se]) p2++;
}
for(int x : A) seen[x]=0;
return V;
}
int main(){
SPEED;
cin >> n >> m >> qsn;
for(int i = 1; i <= m; ++i){
int u, v; cin >> u >> v;
adj[u].eb(v); radj[v].eb(u);
}
for(int i = 1; i <= n; ++i){
bestd[i].eb(0, i);
for(int &j : radj[i]){
bestd[i] = mergevector(bestd[i], bestd[j]);
}
}
while(qsn--){
int city, e;
cin >> city >> e;
for(int i = 1; i <= e; ++i){
cin >> who[i];
busy[who[i]] = true;
}
if(e >= Bz){
fill(d, d + 1 + city, -1);
int res = -1; d[city] = 0;
for(int i = city; i >= 1; --i){
for(int &j : adj[i]){
if(d[j] != -1) maximize(d[i], d[j] + 1);
}
if(!busy[i]) maximize(res, d[i]);
}
cout << res << '\n';
}
else{
int res = -1;
for(pii &v : bestd[city]) if(!busy[v.se]){
maximize(res, v.fi);
break;
}
cout << res << '\n';
}
for(int i = 1; i <= e; ++i) busy[who[i]] = false;
}
return 0;
}
