#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
#ifdef _DEBUG
#define dout(x) clog << "Line " << __LINE__ << ": " << #x << "=" << (x) << el
#else
#define dout(x)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define uid(a,b) uniform_int_distribution<int>(a,b)(rng)
#define ins insert
#define ssize(x) (int((x).size()))
#define bs(args...) binary_search(args)
#define lb(args...) lower_bound(args)
#define ub(args...) upper_bound(args)
#define all(x) (x).begin(),(x).end()
#define mp(a, b) make_pair(a, b)
#define mt(args...) make_tuple(args)
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second
#define die exit(0)
template<typename T>
using vc = vector<T>;
template<typename T>
using uset = unordered_set<T>;
template<typename A, typename B>
using umap = unordered_map<A, B>;
template<typename T, typename Comp>
using pq = std::priority_queue<T, vc<T>, Comp>;
template<typename T>
using maxpq = pq<T, less<T>>;
template<typename T>
using minpq = pq<T, greater<T>>;
template<typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using db = double;
using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pi = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vc<int>;
using vll = vc<ll>;
using vpi = vc<pi>;
using vpll = vc<pll>;
using str = string;
constexpr char el = '\n';
constexpr char sp = ' ';
constexpr int inf = 0x3f3f3f3f;
constexpr ll llinf = 0x3f3f3f3f3f3f3f3fLL;
// ---------------------------------------------------------------------
const int N = 1e5+5;
const int bsz = 350;
int n, m, q;
vi adj[N]; // reversed adj
vpi fur[N];
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
cout << fixed; clog << fixed; clog << unitbuf;
#ifdef _DEBUG
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
freopen("debug.txt", "w", stderr);
#else
//freopen(".in", "r", stdin);
//freopen(".out", "w", stdout);
#endif
cin >> n >> m >> q;
while(m--){
int x, y;
cin >> x >> y;
adj[y].pb(x);
}
// calc fur[]
for(int i = 1; i <= n; ++i){
fur[i].eb(0, i);
for(int j: adj[i]){
vpi ans;
vc<bool> vis(i+1);
int p = 0, p2 = 0;
while((p < ssize(fur[i]) || p2 < ssize(fur[j]))&&ssize(ans)<bsz){
if(p2>=ssize(fur[j])||p<ssize(fur[i])
&&fur[i][p].ff>fur[j][p2].ff+1){
if(!vis[fur[i][p].ss]){
ans.pb(fur[i][p]);
vis[fur[i][p].ss] = 1;
}
++p;
}else{
if(!vis[fur[j][p2].ss]){
ans.eb(fur[j][p2].ff+1, fur[j][p2].ss);
vis[fur[j][p2].ss] = 1;
}
++p2;
}
}
swap(fur[i], ans);
}
}
// print fur[]
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(int i = 1; i <= n; ++i) {
for (auto [d, v]: fur[i])
clog << '(' << d << ", " << v << ") ";
clog << el;
}
clog << el;
#endif
while(q--){
int t, y;
cin >> t >> y;
vi busy;
for(int i = 0; i < y; ++i){
int x;
cin >> x;
busy.pb(x);
}
sort(all(busy));
if(y<bsz){
for(auto[d, v]: fur[t])
if(!bs(all(busy), v)){
cout << d << el;
goto next_query;
}
cout << -1 << el;
}else{
// naive dp
vi dp(t+1);
for(int i = 1; i <= t; ++i){
if(bs(all(busy), i))
dp[i] = -inf;
for(int j: adj[i])
dp[i] = max(dp[i], dp[j]+1);
}
if(dp[t]<0)
cout << -1 << el;
else
cout << dp[t] << el;
}
next_query:;
}
}
