#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int N = 100000 + 5;
const int K = 300;
int n, m, q, indeg[N];
vector<int> adj[N];
pair<int,int> L[N][K];
int sz[N];
pair<int,int> tmp[2*K];
void merge_lists(int u, int v) {
int k = 0;
for(int i = 0; i < sz[u]; i++) tmp[k++] = {L[u][i].first + 1, L[u][i].second};
for(int i = 0; i < sz[v]; i++) tmp[k++] = {L[v][i].first, L[v][i].second};
sort(tmp, tmp + k, [](pair<int,int> &a, pair<int,int> &b){ return a.second < b.second; });
int idx = 0;
for(int i = 0; i < k; ) {
int src = tmp[i].second, best = tmp[i].first, j = i+1;
while(j < k && tmp[j].second == src){ best = max(best,tmp[j].first); j++; }
L[v][idx++] = {best, src};
i = j;
if(idx == K) break;
}
sz[v] = idx;
sort(L[v], L[v] + sz[v], greater<pair<int,int>>());
}
void init() {
int IN[N];
for(int i = 1; i <= n; i++) IN[i] = indeg[i];
queue<int> q;
for(int i = 1; i <= n; i++){
L[i][0] = {0, i};
sz[i] = 1;
if(IN[i] == 0) q.push(i);
}
while(!q.empty()){
int u = q.front(); q.pop();
for(int v: adj[u]){
merge_lists(u,v);
if(--IN[v]==0) q.push(v);
}
}
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(nullptr);
cout.tie(nullptr);
cin >> n >> m >> q;
for(int i = 1; i <= m; i++){
int u,v; cin >> u >> v;
indeg[v]++;
adj[u].push_back(v);
}
init();
while(q--){
int T,Y; cin>>T>>Y;
int C[Y]; unordered_set<int> bad; bad.reserve(Y*2);
for(int i=0;i<Y;i++){ cin>>C[i]; bad.insert(C[i]); }
if(Y <= K){
bool found=0;
for(int i=0;i<sz[T];i++){
if(!bad.count(L[T][i].second)){ cout<<L[T][i].first<<endl; found=1; break; }
}
if(!found) cout<<-1<<endl;
}
else{
queue<int> qq; int IN2[N], ans[N];
for(int i=1;i<=n;i++){ IN2[i]=indeg[i]; ans[i]=0; }
for(int x:bad) ans[x]=-1e18;
for(int i=1;i<=n;i++) if(IN2[i]==0) qq.push(i);
while(!qq.empty()){
int u=qq.front(); qq.pop();
for(int v:adj[u]){
ans[v]=max(ans[v],ans[u]+1);
if(--IN2[v]==0) qq.push(v);
}
}
if(ans[T]<0) cout<<-1<<endl; else cout<<ans[T]<<endl;
}
}
return 0;
}
