#include<iostream>
#define maxn (1<<7)
using namespace std;
int n,k,c;
int a[maxn][maxn],b[maxn];
int main()
{
    cin>>n>>k;
    for(int i=0;i<n;i++)
    {
        cin>>b[i];
        for(int j=0;j<b[i];j++)
        {
            cin>>c;
            a[i][c-1]=1;
        }
    }
    for(int i1=0;i1<n;i1++)
    if(b[i1]==k)
    {
        cout<<"1\n"<<i1+1<<endl;
        return 0;
    }
    for(int i1=0;i1<n-1;i1++)
    for(int i2=i1+1;i2<n;i2++)
    if(b[i1]+b[i2]>=k)
    {
        cout<<"2\n"<<i1+1<<" "<<i2+1<<endl;
        return 0;
    }
    
    for(int i1=0;i1<n-2;i1++)
    for(int i2=i1+1;i2<n-1;i2++)
    for(int i3=i2+1;i3<n;i3++)
    if(b[i1]+b[i2]+b[i3]>=k)
    {
        cout<<"2\n"<<i1+1<<" "<<i2+1<<" "<<i3+1<<endl;
        return 0;
    }
    for(int i=0;i<n-1;i++)
    for(int i1=0;i<n-1;i++)
    for(int i2=0;i<n-1;i++)
    for(int i3=0;i<n-1;i++)
    if(b[i1]+b[i2]+b[i]+b[3]>=k)
    {
        cout<<"2\n"<<i1+1<<" "<<i2+1<<endl;
        return 0;
    }
    cout<<n<<endl;
    for(int i=1;i<n+1;i++)
    cout<<i<<" ";
    cout<<endl;
    return 0;
}