#include<bits/stdc++.h>
#define ffor(i,a,b) for(int i=(a);i<=(b);i++)
#define roff(i,a,b) for(int i=(a);i>=(b);i--)
using namespace std;
const int MAXN=1e5+10,MAXM=400+10;
int n,m,q,len=400,Deg[MAXN],flg[MAXN],deg[MAXN];
vector<int> G[MAXN],g[MAXN]; vector<pair<int,int>> init[MAXN];
vector<pair<int,int>> merge(vector<pair<int,int>> A,vector<pair<int,int>> B) {
vector<pair<int,int>> ans;
ffor(i,0,(int)B.size()-1) B[i].first++;
if(A.empty()) return B;
if(B.empty()) return A;
int ida=0,idb=0;
while(ida<A.size()&&idb<B.size()) {
if(A[ida]>B[idb]) {
if(flg[A[ida].second]==0&&ans.size()<len) flg[A[ida].second]=1,ans.push_back(A[ida]);
ida++;
}
else {
if(flg[B[idb].second]==0&&ans.size()<len) flg[B[idb].second]=1,ans.push_back(B[idb]);
idb++;
}
}
while(ida<A.size()) {
if(flg[A[ida].second]==0&&ans.size()<len) flg[A[ida].second]=1,ans.push_back(A[ida]);
ida++;
}
while(idb<B.size()) {
if(flg[B[idb].second]==0&&ans.size()<len) flg[B[idb].second]=1,ans.push_back(B[idb]);
idb++;
}
for(auto pr:A) flg[pr.second]=0;
for(auto pr:B) flg[pr.second]=0;
return ans;
}
int dp[MAXN];
void solve(int u) {
queue<int> q; int ans=-1;
ffor(i,1,n) dp[i]=-1,deg[i]=Deg[i];
dp[u]=0;
ffor(i,1,n) if(deg[i]==0) q.push(i);
while(!q.empty()) {
int u=q.front(); q.pop();
for(auto v:g[u]) {
deg[v]--; if(deg[v]==0) q.push(v);
if(dp[u]>=0) dp[v]=max(dp[v],dp[u]+1);
}
}
ffor(i,1,n) ans=max(ans,dp[i]);
cout<<ans<<'\n';
return ;
}
int main() {
ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>n>>m>>q;
ffor(i,1,m) {int u,v; cin>>u>>v,G[u].push_back(v),g[v].push_back(u),deg[v]++,Deg[u]++;}
queue<int> que; ffor(i,1,n) if(deg[i]==0) que.push(i);
while(!que.empty()) {
int u=que.front(); que.pop();
if(init[u].size()<len) init[u].push_back({0,u});
for(auto v:G[u]) {
deg[v]--,merge(init[v],init[u]);
if(deg[v]==0) que.push(v);
}
}
ffor(i,1,q) {
int u,cnt; cin>>u>>cnt;
vector<int> id;
ffor(j,1,cnt) {int v; cin>>v,id.push_back(v),flg[v]=1;}
if(cnt<=len) {
int ans=-1;
for(auto pr:init[u]) if(flg[pr.second]==0&&pr.second!=u) {ans=pr.first;break;}
cout<<ans<<'\n';
}
else solve(u);
for(auto v:id) flg[v]=0;
}
return 0;
}
