#include <cstdio>
#include <iostream>
#include <algorithm>
#define MAXN 30
using namespace std;

char graph[MAXN+1][MAXN+1];
int cnt[2];
int n,m;

int sign(int x)
{
    if(x==0)
    {
        return 0;
    }
    else
    {
        return 1;
    }
}

int main()
{
    int i,j,k,s,minimum;
    n=0;
    while(scanf("%d",&i)!=EOF)
    {
        scanf("%d",&m);
        for(k=0;k<m;k++)
        {
            scanf("%d",&j);
            graph[i][j]=graph[j][i]=1;
        }
        n=max(n,i);
    }
    minimum=1000000000;
    for(i=(1<<n)-1;i>=0;i--)
    {
        m=cnt[0]=cnt[1]=0;
        for(j=0;j<n;j++)
        {
            s=sign(i&(1<<j));
            if(s!=0)
            {
                m++;
            }
            for(k=0;k<n;k++)
            {
                if((k!=j)&&(graph[k][j]==0)&&(s==sign(i&(1<<k))))
                {
                    cnt[s]++;
                    break;
                }
            }
        }
        if(m==(n>>1))
        {
            minimum=min(minimum,min(cnt[0],cnt[1]));
        }
    }
    printf("%d\n",minimum);
    return 0;
}