#include<bits/stdc++.h>
using namespace std;
using I=int;
using B=bool;
const I N=100000;
const I Y=100000;
const I MAX=1e9;
const I MIN=-MAX;
vector<I>adjs[N];
vector<pair<I,I>>tops[N];
priority_queue<tuple<I,I,I,I>>ques;
I c_arr[Y];
B uses[N];
B viss[N];
B bsys[N];
I diss[N];
I tims[N];
I tim=1;
I siz;
void dfs1(I a){
if(viss[a])return;
viss[a]=1;
for(auto b:adjs[a])dfs1(b);
while(ques.size())ques.pop();
ques.push({0,a,a,MAX});
for(auto b:adjs[a]){
auto[dis,x]=tops[b][0];
ques.push({dis+1,x,b,0});
}
while(tops[a].size()<siz&&ques.size()){
auto[dis1,x,b,i]=ques.top();ques.pop();
if(!uses[x])tops[a].push_back({dis1,x}),uses[x]=1;
if(i+1<tops[b].size()){
auto[dis2,y]=tops[b][i+1];
ques.push({dis2+1,y,b,i+1});
}
}
for(auto[dis,x]:tops[a])uses[x]=0;
}
I dfs2(I a){
if(tims[a]==tim)return diss[a];
tims[a]=tim,diss[a]=bsys[a]?MIN:0;
for(auto b:adjs[a])if(dfs2(b)!=MIN)diss[a]=max(diss[a],diss[b]+1);
return diss[a];
}
I main(){
cin.tie(0)->sync_with_stdio(0);
I n,m,q;cin>>n>>m>>q;
for(I i=0;i<m;i++){
I s,e;cin>>s>>e,s--,e--;
adjs[e].push_back(s);
}
siz=max(sqrt(n)/2.5,1.);
for(I i=n-1;i>=0;i--)dfs1(i);
while(q--){
I t,y;cin>>t>>y,t--;
for(I i=0;i<y;i++){I c;cin>>c,bsys[c_arr[i]=c-1]=1;}
I res=MIN;
for(auto[dis,i]:tops[t])if(!bsys[i]){res=dis;break;}
if(res==MIN&&y>=siz)res=dfs2(t);
printf("%i\n",dfs2(t)==MIN?-1:diss[t]),tim++;
for(I i=0;i<y;i++)bsys[c_arr[i]]=0;
}
}
