#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using ll = long long;
using ii = pair<int,int>;
using aa = array<int,3>;
const int B=400;
vector<int> a[100005],adj[100005];
vector<ii> ans[100005];
int mp[100005];
int d[100005];
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
int n,m,q;
cin >> n >> m >> q;
for(int i=1;i<=m;i++) {
int u,v;
cin >> u >> v;
adj[v].push_back(u);
}
for(int i=1;i<=n;i++) {
sort(adj[i].begin(),adj[i].end());
adj[i].erase(unique(adj[i].begin(),adj[i].end()),adj[i].end());
}
for(int i=1;i<=n;i++) {
ans[i].push_back({0,i});
for(int v:adj[i]) {
vector<ii> mer;
int j=0;
for(ii x:ans[i]) {
while(j<ans[v].size() && make_pair(ans[v][j].fi+1,ans[v][j].se)>=x) {
if(!mp[ans[v][j].se]) mer.push_back({ans[v][j].fi+1,ans[v][j].se});
mp[ans[v][j].se]=1;
j++;
}
if(!mp[x.se]) mer.push_back(x);
mp[x.se]=1;
}
for(ii x:mer) {
mp[x.se]=0;
}
mer.erase(unique(mer.begin(),mer.end()),mer.end());
while(mer.size()>B) mer.pop_back();
ans[i]=mer;
}
}
while(q--) {
int u,k;
cin >> u >> k;
vector<int> sigma;
for(int i=1;i<=k;i++) {
int x;
cin >> x;
sigma.push_back(x);
mp[x]=1;
}
if(k<B) {
bool t=1;
for(ii x:ans[u]) {
if(!mp[x.se]) {
cout << x.fi << '\n';
t=0;
break;
}
}
if(t) {
cout << "-1\n";
}
}
else {
for(int i=1;i<=u;i++) {
if(mp[i]) d[i]=-1e9;
}
for(int i=1;i<=u;i++) {
for(int v:adj[i]) {
d[i]=max(d[i],d[v]+1);
}
}
if(d[u]<0) cout << "-1\n"; else
cout << d[u] << '\n';
for(int i=1;i<=n;i++) {
d[i]=0;
}
}
for(int x:sigma) {
mp[x]=0;
}
}
return 0;
}
