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#include<bits/stdc++.h>
using namespace std;
vector<int> xd[500005];
vector<int> res[500005];

void printxd()
{
    for(int i=1;i<10;i++)
    {for (size_t j = 0; j < xd[i].size(); j++)
    {   
        cerr<< xd[i][j] <<" ";
    }
    cerr<<endl;
    }
}

void printres()
{
    for(int i=1;i<10;i++)
    {for (size_t j = 0; j < res[i].size(); j++)
    {   
        cerr<< res[i][j] <<" ";
    }
    cerr<<endl;
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    int n,k;
    int a,b;
    cin>>k>>n;
    if(k==1)
    {
        cout<<n<<endl;return 0;
    }
    for(int i=0;i<n;i++)
    {
        xd[1].push_back(0);
        res[1].push_back(0);
    }
    for(int i=2;i<=k;i++)
    {
        cin>>a;
        for(int j=0;j<a;j++)
        {
            cin>>b;
            xd[i].push_back(b-1);
            res[i].push_back(0);
        }
    }
    for(int i=0;i<xd[k].size();i++)
    res[k][i]=1;

    //printxd();
    //printres();
    for(int i = k; i>1;i--)
    {
        for(int j=0;j<xd[i].size();j++)
        {
            if(res[i][j]==0)
                res[i][j]=1;
            if(xd[i][j]>=0)
            {
                if(i==2)
                {
                    //cerr<<"dodano "<<res[i][j]<<" do res["<<i-1<<"]["<<xd[i][j]<<"]"<<endl;
                }
                res[i-1][xd[i][j]]+=res[i][j];
            }
            
        }
    }
    //cerr<<"tu "<<endl;//i<<" "<<j<<" "<<xd[i][j]<<" "<<res[i][j]<<endl;
        for(int i=0;i<n;i++)
    if(res[1][i]==0)
    res[1][i]=1;
    int ret = 0;
    for(int i=1;i<=k;i++)
    {
        int sum =0;
        for(int j=0;j<xd[i].size();j++)
        {
            sum+=res[i][j];
        }
        ret=max(ret,sum);
    }
    //printres();
    cout<<ret<<endl;
}