#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#define FOR(i,a,b) for(int i=a;i<=b;++i)
#define PII pair<int,int>
#define ll long long
#define pb push_back
#define sz(x) (int)(x.size())
#define gc getchar()
#define mk make_pair
#define gc (_p1==_p2&&(_p2=(_p1=_buf)+fread(_buf,1,100000,stdin),_p1==_p2)?EOF:*_p1++)
using namespace std;
char _buf[100000],*_p1=_buf,*_p2=_buf;
inline int gi()
{
int x=0,f=1;
char ch=gc;
while(ch<'0'||ch>'9')
{
if(ch=='-')f=-1;
ch=gc;
}
while(ch>='0'&&ch<='9')
{
x=(x<<3)+(x<<1)+(ch^48);
ch=gc;
}
return (f==1)?x:-x;
}
const int maxn=2e5+5,B=210,inf=1e9;
priority_queue<pair<int,int>>pq[maxn];
int ind[maxn],tmp[maxn],c[maxn];
vector<int>e[maxn];
int dp[maxn],n,m,Q,t,y;
inline void input()
{
n=gi(),m=gi(),Q=gi();
FOR(i,1,m)
{
int u=gi(),v=gi();
e[u].pb(v);tmp[v]++;
}
}
bool vis[maxn];
int q[maxn],hd,tl;
inline void count()
{
FOR(i,1,n)ind[i]=tmp[i],dp[i]=-inf;
hd=0,tl=-1;
FOR(i,1,n)if(!ind[i])q[++tl]=i;
FOR(i,1,n)if(!vis[i])dp[i]=0;
while(hd<=tl)
{
int u=q[hd++];
for(int v:e[u])
{
dp[v]=max(dp[u]+1,dp[v]);
ind[v]--;
if(ind[v]==0)q[++tl]=v;
}
}
printf("%d\n",dp[t]<0?-1:dp[t]);
}
inline void count2()
{
priority_queue<pair<int,int>>pq=::pq[t];
while(!pq.empty())
{
auto [w,id]=pq.top();
pq.pop();
if(vis[id])continue;
else {return printf("%d\n",w),void();}
}
puts("-1");
}
bool bk[maxn];
inline auto merge(int x,int y)
{
priority_queue<pair<int,int>>q,q1=pq[x],q2=pq[y];
vector<int>temp;
while(sz(temp)<=B)
{
if(q1.empty()&&q2.empty())break;
pair<int,int>v;
if(q1.empty())v=q2.top(),v.first++,q2.pop();
else if(q2.empty())v=q1.top(),q1.pop();
else if(q1.top().first>q2.top().first)v=q1.top(),q1.pop();
else v=q2.top(),q2.pop(),v.first++;
if(!bk[v.second])q.push(v),bk[v.second]=1,temp.pb(v.second);
}
for(int x:temp)bk[x]=0;
return q;
}
inline void solve()
{
queue<int>q;
FOR(i,1,n)ind[i]=tmp[i],pq[i].push({0,i});
FOR(i,1,n)if(!ind[i])q.push(i);
while(!q.empty())
{
int u=q.front();q.pop();
for(int v:e[u])
{
pq[v]=merge(v,u),ind[v]--;
if(ind[v]==0)q.push(v);
}
}
FOR(i,1,Q)
{
t=gi(),y=gi();
FOR(j,1,y)c[j]=gi();
FOR(j,1,y)vis[c[j]]=1;
if(y>=B)count();
else count2();
FOR(j,1,y)vis[c[j]]=0;
}
}
int main()
{
//freopen("03-06.in","r",stdin);
//freopen("03-06.out","w",stdout);
input();
solve();
return 0;
}
