#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
const int N = 1e5 + 5 , B = 320;
vector<int> adj[N];
vector<pair<int,int>> dp[N];
bool vis[N];
void solve(int node){
if(dp[node].size()) return;
for(auto ch : adj[node]) solve(ch);
priority_queue<array<int,3>> q;
for(auto ch : adj[node]){
q.push({dp[ch][0].first+1,ch,0});
}
vis[node] = 1;
while(q.size() && dp[node].size() <= B){
auto [_,ch,idx] = q.top(); q.pop();
if(vis[dp[ch][idx].second]) goto gt;
dp[node].push_back({_,dp[ch][idx].second});
vis[dp[ch][idx].second] = 1;
gt:
if(idx + 1 < (int)dp[ch].size()) q.push({dp[ch][idx+1].first+1,ch,idx+1});
}
dp[node].push_back({0,node});
for(auto [_,x] : dp[node]) vis[x] = 0;
}
bool mark[N];
int dp2[N];
int solve2(int node){
int &ret = dp2[node];
if(ret != -1) return dp2[node];
ret = (mark[node] ? -1e9 : 0);
for(auto ch : adj[node]){
ret = max(ret , solve2(ch) + 1);
}
return ret;
}
void solve(){
int n,m,q;
cin>>n>>m>>q;
vector<int> deg(n+1);
for(int i=0;i<m;i++){
int a,b;
cin>>a>>b;
deg[a] ++;
adj[b].push_back(a);
}
for(int i=1;i<=n;i++){
if(deg[i]) continue;
solve(i);
}
while(q--){
int node,sz;
cin>>node>>sz;
vector<int> v(sz);
for(auto &i:v) cin>>i;
if(sz <= B){
for(auto i : v) mark[i] = 1;
for(auto [d,x] : dp[node]){
if(mark[x]) continue;
cout<<d<<endl;
goto gt;
}
cout<<-1<<endl;
gt:
for(auto i : v) mark[i] = 0;
}
else {
memset(dp2,-1,sizeof(dp2));
for(auto i : v) mark[i] = 1;
cout<<(solve2(node)<0?-1:solve2(node))<<endl;
for(auto i : v) mark[i] = 0;
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
