#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<vpii> vvpii;
typedef vector<vpll> vvpll;
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
#define fi first
#define se second
template<class T> bool ckmin(T &a, const T &b) {return a > b ? a = b, 1 : 0;}
template<class T> bool ckmax(T &a, const T &b) {return a < b ? a = b, 1 : 0;}
namespace debug {
void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for(auto z : x) cerr << (f++ ? "," : ""), __print(z); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if(sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef ljuba
#define dbg(x...) cerr << "\e[91m" << "LINE(" << __LINE__ << ") -> " << "[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif
}
using namespace debug;
const char nl = '\n';
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
/*
погледај сампле тестове, пре него што имплементираш (можда имаш погрешну идеју)
уместо да разматраш неке глупе случајеве на папиру, размишљај заправо о задатку
*/
const int mxN = 1e5 + 12;
const int K = 250;
const int INF = 1e9 + 12;
vi adj2[mxN];
int kosta[mxN];
vpii moze[mxN];
void solve() {
int n, m, q;
cin >> n >> m >> q;
for(int i = 0; i < m; ++i) {
int u, v;
cin >> u >> v;
--u, --v;
adj2[v].pb(u);
}
{
//William Lin's idea
vi prosli(n);
for(int i = 0; i < n; ++i) {
vi moguci{i};
for(auto e : adj2[i]) {
for(auto z : moze[e]) {
if(!prosli[z.se]) {
moguci.pb(z.se);
}
ckmax(prosli[z.se], z.fi + 1);
}
}
nth_element(moguci.begin(), moguci.begin()+min(K, sz(moguci)), moguci.end(), [&](int a, int b) {
return prosli[a] > prosli[b];
});
for(int j = 0; j < min(K, sz(moguci)); ++j) {
int x = moguci[j];
moze[i].pb({prosli[x], x});
}
for(auto z : moguci) prosli[z] = 0;
}
}
for(int i = 0; i < n; ++i) {
dbg(i, moze[i]);
}
vector<bool> marked(n);
for(int iter = 0; iter < q; ++iter) {
int s;
cin >> s;
--s;
int ima;
cin >> ima;
vi bruh(ima);
for(auto &z : bruh) cin >> z, --z;
for(auto z : bruh) {
marked[z] = true;
}
int odg = -1;
if(ima <= K) {
for(auto z : moze[s]) {
if(!marked[z.se]) {
ckmax(odg, z.fi);
}
}
} else {
//dp
vi dp(n, -INF);
for(int i = 0; i < n; ++i) {
if(marked[i]) dp[i] = -INF;
else dp[i] = 0;
for(auto e : adj2[i]) {
ckmax(dp[i], dp[e] + 1);
}
}
odg = dp[s];
if(odg < 0) odg = -1;
}
cout << odg << nl;
for(auto z : bruh) {
marked[z] = false;
}
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int testCases = 1;
//cin >> testCases;
while(testCases--)
solve();
}
