#include<iostream>
#include<cstdio>
#include<iomanip>
#include<string>
#include<cstring>
#include<algorithm>
using namespace std;
int a,x[100000],p,w[10000],q[10000][10000],h[10000]={0},t=0;
int wx=1000000007;
int main()
{
	freopen("three_squirrels.in","r",stdin);
	freopen("three_squirrels.out","w",stdout);
	cin>>a;
	x[0]=1;
	h[0]=1;
	for(int i=1;i<=a;i++)
	{
		cin>>w[i];
		for(int j=1;j<=w[i];j++)
			cin>>q[i][j];
	}
	for(int k=1;k<=a;k++)
	{
	for(int i=1;i<=a;i++)
	{
		t=0;
		if(h[i]==1) continue;
		for(int j=1;j<=w[i];j++)
		{
			if(h[q[i][j]]==1) t++;
		}
		if(t==w[i]) 
			{for(int j=1;j<=w[i];j++)
			{x[i]=((x[i]%wx)+(x[q[i][j]]%wx))%wx;}
			h[i]=1;
			}
	}
	int l=0;
	for(int i=1;i<=a;i++)
	{
		if(h[i]==1) l++;
	}
	if(l==a) break;
	}
	cout<<x[a]<<endl;
	return 0;
}