#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
using namespace std;
int n,num2=0,sum;
int b[110000]={};
string a[110000];
void find(int x)
{
	int num4=0;
	for(int i=0;;)
	{
		if(a[x][i]!=' ')
		{
			num4+=num4*10+a[x][i]-'0';
			i++;
			if(i>a[x].size()) break;
		}
		if(a[x][i]==' ')
		{
			i++;
			if(i>a[x].size()) break;
			for(;;)
			{
				if(b[num4]!=0)
				{
					b[x]+=b[num4]%1000000007;
					num4=0;
					break;
				}
				find(num4);
			}
		}
	}
}
int main()
{
	freopen("three_squirrels.in","r",stdin);
	freopen("three_squirrels.out","w",stdout);
	scanf("%d",&n);
	b[0]=1;
	for(int i=1;i<=n;i++)
	{
		int m;
		cin>>m;
		for(int j=1;j<=m;j++)
		{
			string x;
			cin>>x;
			a[i]+=x;
			a[i]+=' ';
		}
	}
	find(n);
	cout<<b[n]<<endl;
	return 0;
}