#include<iostream>
#include<iomanip>
#include<cmath>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
struct ss
{
	int num;
	long long b[11];
	long long sum;
}a[100010]={};
long long n,a1=1000000007;
int dfs(int k)
{
	if(k==0)
		return 1;
	long long sum1=0;
	for(int i=1;i<=a[k].num;i++)
	{
		if(a[a[k].b[i]].sum!=0)
			sum1+=a[a[k].b[i]].sum;
		else
			sum1+=dfs(a[k].b[i]);
		sum1%=a1;
	}
	a[k].sum=sum1;
	return sum1;
}
int main()
{
	freopen("three_squirrels.in","r",stdin);
	freopen("three_squirrels.out","w",stdout);
	memset(a,0,sizeof(a));
	cin>>n;
	a[0].sum=1;
	int yu=0;
	for(int i=1;i<=n;i++)
	{
		int k;
		cin>>k;
		a[i].num=k;
		for(int j=1;j<=k;j++)
		{	
			long long z;
			if(z>i)
				yu=1;
			cin>>z;
			a[i].b[j]=z;
		}
	}
	if(yu==1)
		cout<<dfs(n)<<endl;
	else
	{
		for(int i=1;i<=n;i++)
		{
			for(int j=1;i<=a[i].num;j++)
			{
				a[i].sum+=a[i].b[j];
				a[i].sum%=a1;
			}
		}
		cout<<a[n].sum<<endl;
	}
	return 0;
}