#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define fi first
#define in inline
#define se second
#define mp make_pair
#define pb push_back
const int N = 1e5+10;
const ll mod = 1e9+7;

ll read(){
	ll x = 0,f = 1;char c = getchar();
	for(;c < '0' || c > '9';c = getchar())if(c == '-')f = -1;
	for(;c >= '0' && c <= '9';c = getchar())x = (x<<1) + (x<<3) + c-'0';
	return x * f;
}

int n;
ll f[N];
int nx[N][12],l[N];
ll dfs(int x){
	if(f[x] != -1)return f[x];
	ll ans = 0;
	for(int i = 1;i <= l[x];i++)(ans += dfs(nx[x][i])) %= mod;
	return f[x] = ans;
}
int main(){
	freopen("three_squirrels.in","r",stdin);
	freopen("three_squirrels.out","w",stdout);
	n = read();
	memset(f,-1,sizeof f);
	f[0] = 1;
	for(int i = 1;i <= n;i++){
		l[i] = read();
		for(int j = 1;j <= l[i];j++)nx[i][j] = read();
	}
	printf("%lld\n",dfs(n));

	return 0;

}