#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int B = 250;
bool apagados[100010];
bool ok[100010];
int dp[100010];
int n,m,q;
bool comp(pair<int,int> a , pair<int,int> b){
if(a.first < b.first){
return false;
}
if(a.first > b.first){
return true;
}
return (a.second < b.second);
}
vector<pii> juntar(vector<pii> a, vector<pii> b){
int ini1 = 0,ini2 = 0;
vector<pii> vec;
vector<int> app;
while((ini1 != a.size()) || (ini2 != b.size())){
int flag = -1;
if(ini1 == a.size()){
flag = 1;
}
else if(ini2 == b.size()){
flag = 0;
}
else if(a[ini1].first > b[ini2].first){
flag = 0;
}
else{
flag = 1;
}
if(flag == 0){
int s = a[ini1].second;
if(!ok[s]){
app.push_back(s);
ok[s] = true;
vec.push_back(a[ini1]);
}
ini1++;
}
else{
int s = b[ini2].second;
if(!ok[s]){
app.push_back(s);
ok[s] = true;
vec.push_back(b[ini2]);
}
ini2++;
}
}
for(auto u : app){
ok[u] = false;
}
app.clear();
return vec;
}
vector<int> adj[100010];
signed main(){
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> q;
for(int i = 1;i <= m;i++){
int a,b;
cin >> a >> b;
adj[b].push_back(a);
}
vector<pair<int,int>> dist[100010];
for(int i = 1;i <= n;i++){
dist[i].push_back({0 , i});
}
for(int i = 1;i <= n;i++){
for(auto u : adj[i]){
vector<pair<int,int>> c,d;
c.clear();
for(auto l : dist[u]){
c.push_back({l.first + 1,l.second});
}
d = dist[i];
dist[i].clear();
dist[i] = juntar(c, d);
if(dist[i].size() > B + 1){
dist[i].resize(B + 1);
}
}
}
for(int i = 1;i <= n;i++){
dist[i].push_back({-1 , 0});
}
for(int i = 1;i <= q;i++){
int t,y;
cin >> t >> y;
vector<int> atual;
for(int j = 1;j <= y;j++){
int a;
cin >> a;
atual.push_back(a);
apagados[a] = true;
}
if(y <= B){
for(auto u : dist[t]){
if(!apagados[u.second]){
cout << u.first << "\n";
break;
}
}
}
else{
int ans = -1;
for(int i = 1;i <= n;i++){
dp[i] = -1e9;
}
dp[t] = 0;
for(int i = t + 1;i >= 1;i--){
for(auto u : adj[i]){
dp[u] = max(dp[u] , dp[i] + 1);
}
if(!apagados[i]){
ans = max(ans , dp[i]);
}
}
cout << ans << "\n";
}
for(auto u : atual){
apagados[u] = false;
}
atual.clear();
}
}
