C++ :

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<set>
#include<iostream>
#include<queue>
#include<vector>
#include<cmath>
#include<stack>
#include<iterator>
#include<algorithm>
using namespace std;
set<int> s[1000],ans,ans1,ans2;
queue<int> q;
int main()
{
    int i,n,m,j,t,w;
    set<int>::iterator it;
    for(i=0;i<1000;i++)
        s[i].clear();
    scanf("%d%d",&m,&n);
    for(i=1;i<=m;i++)
    {
        scanf("%d",&t);
        for(j=0;j<t;j++)
        {
            scanf("%d",&w);
            s[i].insert(w);
        }
    }
    for(i=0;i<n;i++)
    {
        while(!q.empty())
            q.pop();
        ans.clear();
        ans1.clear();
        ans2.clear();
        scanf("%d",&t);
        ans1=s[t];
        ans2=ans1;
        while(1)
        {
            scanf("%d",&w);
            if(w==0)
                break;
            set_intersection(ans1.begin(),ans1.end(),s[w].begin(),s[w].end(),insert_iterator<set<int> >(ans,ans.begin()));
            ans1=ans;
            ans2=ans;
            ans.clear();
        }
        if(ans2.size()==0)
        {
            printf("NULL\n");
            continue;
        }
        for(it=ans2.begin();it!=ans2.end();++it)
            q.push(*it);
        while(1)
        {
            if(q.size()==1)
                break;
            w=q.front();
            printf("%d ",w);
            q.pop();
        }
        w=q.front();
        q.pop();
        printf("%d\n",w);
    }
    return 0;
}