#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5, S = 200;
int n, m, q;
vector < pair < int, int > > dp[N];
vector < int > g[N];
bool used[N];
int dpp[N], ans[N];
inline void mrg(int x, int y){
for(auto it : dp[x]){
ans[it.second] = it.first;
}
for(auto it : dp[y]){
ans[it.second] = max(ans[it.second], it.first + 1);
}
for(auto &it : dp[x]){
it.first = ans[it.second];
ans[it.second] = 0;
}
for(auto it : dp[y]){
if(ans[it.second]){
dp[x].push_back(make_pair(it.first + 1, it.second));
ans[it.second] = 0;
}
}
sort(dp[x].rbegin(), dp[x].rend());
while((int)dp[x].size() > S){
dp[x].pop_back();
}
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n >> m >> q;
for(int i = 1; i <= m; i++){
int x, y;
cin >> x >> y;
g[y].push_back(x);
}
for(int i = 1; i <= n; i++){
for(int j : g[i]){
mrg(i, j);
}
if((int)dp[i].size() < S){
dp[i].push_back(make_pair(0, i));
}
}
while(q--){
int v, x;
cin >> v >> x;
vector < int > y(x);
for(int i = 0; i < x; i++){
cin >> y[i];
used[y[i]] = true;
}
if(x < S){
for(auto it : dp[v]){
if(!used[it.second]){
cout << it.first << "\n";
goto to;
}
}
cout << "-1\n";
to:;
}
else{
for(int i = 1; i <= v; i++){
dpp[i] = 0;
if(used[i]){
dpp[i] = -1;
}
for(int j : g[i]){
if(dpp[j] != -1){
dpp[i] = max(dpp[i], dpp[j] + 1);
}
}
}
cout << dpp[v] << "\n";
}
for(int i = 0; i < x; i++){
used[y[i]] = false;
}
y.clear();
}
}
