#include<bits/stdc++.h>
using namespace std;

const int maxn = 1e5 + 5;
const int SQ = 320;
vector<int> g[maxn];
vector<pair<int , int> > BSQ[maxn];
bool vis[maxn] , mark[maxn];
int n , m , q;

void relax(int v){
	for(int u : g[v]){
		vector<pair<int , int> > vec;
		while(!BSQ[v].empty()){
			vec.push_back(BSQ[v].back());
			BSQ[v].pop_back();
		}

		int jv = 0 , ju = 0;
		while(ju < (int)BSQ[u].size() && jv < (int)vec.size() && BSQ[v].size() < SQ){
			while(ju < (int)BSQ[u].size() && vis[BSQ[u][ju].second])
				ju++;
			while(jv < (int)vec.size() && vis[vec[jv].second])
				jv++;
			if(ju == (int)BSQ[u].size() || jv == (int)vec.size())
				break;
			if(BSQ[u][ju].first + 1 > vec[jv].first){
				BSQ[v].push_back({BSQ[u][ju].first + 1 , BSQ[u][ju].second});
				vis[BSQ[u][ju].second] = true;
				ju++;
			}
			else{
				BSQ[v].push_back(vec[jv]);
				vis[vec[jv].second] = true;
				jv++;
			}
		}

		while(ju < (int)BSQ[u].size() && BSQ[v].size() < SQ){
			while(ju < (int)BSQ[u].size() && vis[BSQ[u][ju].second])
				ju++;
			if(ju == (int)BSQ[u].size())
				break;
			BSQ[v].push_back({BSQ[u][ju].first + 1 , BSQ[u][ju].second});
			ju++;
		}

		while(jv < (int)vec.size() && BSQ[v].size() < SQ){
			while(jv < (int)vec.size() && vis[vec[jv].second])
				jv++;
			if(jv == (int)vec.size())
				break;
			BSQ[v].push_back(vec[jv]);
			jv++;
		}

		if(BSQ[v].size() < SQ && !vis[u]){
			BSQ[v].push_back({1 , u});
			vis[u] = true;
		}

		for(auto i : BSQ[v])
			vis[i.second] = false;
	}
}

int main(){
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m >> q;
	for(int i = 0 ; i < m ; i++){
		int u , v;
		cin >> u >> v;
		g[v].push_back(u);
	}

	for(int i = 1 ; i <= n ; i++)
		relax(i);

	while(q--){
		int ver , k;
		cin >> ver >> k;
		vector<int> in;
		for(int i = 0 ; i < k ; i++){
			int x;
			cin >> x;
			in.push_back(x);
			mark[x] = true;
		}

		if(k < SQ){
			int ans = -1;
			for(auto i : BSQ[ver]){
				if(!mark[i.second]){
					ans = max(ans , i.first);
				}
			}

			if(ans == -1){
				if(mark[ver]){
					cout << -1 << '\n';
				}
				else{
					cout << 0 << '\n';
				}
			}
			else{
				cout << ans << '\n';
			}
		}
		else{
			int dp[ver + 1];
			for(int i = 1 ; i <= ver ; i++){
				dp[i] = 0;
				for(int u : g[i]){
					if(dp[u] == -1) continue;
					dp[i] = max(dp[i] , dp[u] + 1);
				}

				if(dp[i] == 0 && mark[i]){
					dp[i] = -1;
				}
			}

			cout << dp[ver] << '\n';
		}

		for(int i : in)
			mark[i] = false;
	}
    return 0;
}