#include <bits/stdc++.h>
#include <ext/rope>
using namespace std;
using namespace __gnu_cxx;
#pragma GCC optimize("-Ofast")
#pragma GCC optimize("-O1")
//-------------------------------------------------------------//
typedef long long ll;
typedef unsigned long long ull;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PI acos(-1)
#define lb lower_bound
#define ub upper_bound
#define endl '\n'
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define sum_to(n) (n*(n+1))/2
#define pb push_back
#define pf push_front
#define fil(arr,x) memset(arr,x,sizeof(arr))
const ll mod=1e9+7;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,-1,1};
//-------------------------------------------------------------//
ll lcm(ll a,ll b)
{
return (max(a,b)/__gcd(a,b))*min(a,b);
}
void person_bool(bool x)
{
cout<<(x?"YES":"NO")<<endl;
}
const int N=1e5+5,B=316;
vector<int>adj[N];
vector<pair<int,int>>vec[N];
int dp[N];
bool vis[N];
int temp[N];
bool deleted[N];
bool g[N];
vector<int>dist[N];
void dfs(int node){
vis[node]=1;
for(auto i:adj[node])
if(!vis[i])
dfs(i);
vector<int>k;
for(auto i:adj[node])
for(auto j:vec[i])
temp[j.first]=max(temp[j.first],j.second+1),k.push_back(j.first);
k.push_back(node);
int mx=0;
for(auto i:k){
if(!g[i]){
g[i]=1;
dist[temp[i]].push_back(i);
mx=max(mx,temp[i]);
}
}
for(int i=mx;i>=0;i--){
for(auto j:dist[i]){
if(vec[node].size()==B)break;
vec[node].push_back({j,i});
}
if(vec[node].size()==B)break;
}
for(auto i:k){
g[i]=0;
dist[temp[i]].clear();
temp[i]=0;
}
}
int main()
{
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
fast
int n,m,q;
cin>>n>>m>>q;
for(int i=0;i<m;i++){
int u,v;
cin>>u>>v;
adj[v].push_back(u);
}
for(int i=1;i<=n;i++)
if(!vis[i])
dfs(i);
while(q--){
int t,y;
cin>>t>>y;
vector<int>c;
for(int i=0;i<y;i++){
int x;
cin>>x;
if(x<=t)c.push_back(x),deleted[x]=1;
}
y=c.size();
if(y<B){
int ans=-1;
for(auto i:vec[t]){
if(!deleted[i.first]){
ans=i.second;
break;
}
}
cout<<ans<<endl;
}
else{
fil(dp,-1);
for(int i=1;i<=t;i++){
if(!deleted[i])dp[i]=0;
for(auto j:adj[i])
dp[i]=max(dp[i],(dp[j]>0?dp[j]+1:deleted[j]?deleted[i]*-1:1));
}
cout<<dp[t]<<endl;
}
for(auto i:c)deleted[i]=0;
}
return 0;
}
