#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <string>
#include <cmath>
#include <ctime>
using namespace std;
inline int read()
{
	int x=0,f=1;char ch=getchar();
	while (ch>'9'||ch<'0')	{if (ch=='-'){f=-1;} ch=getchar();}
	while (ch<='9'&&ch>='0'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}
	return x*f;
}
int n,len=0;
int q[101000]={};
int nextt[101000][20]={};
int t[101000]={},k[101000]={};
struct edge{int y,next;}e[1001000];
int _link[101000]={};
bool flag[101000]={};
long long num[101000]={};
int maxx=0;
inline void insert(int a,int b)
{
	e[++len].next=_link[a];_link[a]=len;e[len].y=b;
}
void init()
{
	n=read();
	memset(e,0,sizeof(e));
	for (int i=1;i<=n;i++){	
		t[i]=read();k[i]=t[i];
		for (int j=1;j<=t[i];j++)	{nextt[i][j]=read();insert(nextt[i][j],i);}
	}
	maxx=1000000007;
}
inline void sum(int now)
{
	for (int i=1;i<=t[now];i++)	{num[now]+=num[nextt[now][i]];if (num[now]>maxx)num[now]%=maxx;}
}
void bfs()
{
	memset(q,0,sizeof(q));
	memset(num,0,sizeof(num));
	q[1]=0;num[0]=1;
	int head=1,tail=1;
	while (head<=tail){
		for (int i=_link[q[head]];i;i=e[i].next) {
			num[e[i].y]+=num[q[head]];if (num[e[i].y]>maxx)	num[e[i].y]%=maxx;
			if (--k[e[i].y]==0)	{q[++tail]=e[i].y;flag[e[i].y]=true;}
		}
		head++;
	}
	for (int i=1;i<=n;i++)	if (!flag[i])	sum(i);
}
int main()
{
	freopen("three_squirrels.in","r",stdin);
	freopen("three_squirrels.out","w",stdout);
	init();
	bfs();
	cout<<num[n]<<endl;
	
	return 0;
}