#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); i--)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

const int mod = 1e9 + 7;
int add(int a, int b)
{
	return a + b < mod ? a + b : a + b - mod;
}
int sub(int a, int b)
{
	return a - b >= 0 ? a - b : a - b + mod;
}
int mult(int a, int b)
{
	return (LL)a * b % mod;
}
int binpow(int a, int n)
{
	int res = 1;
	while(n)
	{
		if(n & 1)
			res = mult(res, a);
		a = mult(a, a);
		n /= 2;
	}
	return res;
}

struct Fenwick
{
	int n;
	vector<LL> v;
	
	void init(int _n)
	{
		n = _n;
		v.assign(n, 0);
	}
	
	void upd(int i, int x)
	{
		for (; i < n; i |= (i + 1))
			v[i] = add(v[i], x);
	}
	
	LL query(int i)
	{
		LL ans = 0;
		for (; i >= 0; i = (i & (i + 1)) - 1)
			ans = add(ans, v[i]);
		return ans;
	}	
};


const int N = 1 << 18;
VI r[N];

int level[N], cnt[N];

void solve(int n, int m)
{
	FOR(i, 0, n + 1)
	{
		int k;
		if(i != n)
			cin >> k;
		else
			k = m;
		r[i].resize(k);
		FOR(j, 0, k)
			cin >> r[i][j];
	}
	FOR(i, 0, m + 1)
		level[i] = -1;
		
	set<int> poses;
	FOR(i, 0, n)
		poses.insert(i);
	set<int> uniq;
	
	int lvl = 0;
	while(SZ(poses))
	{
		cnt[lvl] = 0;
		VI del;
		for(int i : poses)
		{
			int cur = r[i][lvl];
			if(!uniq.count(cur))
			{
				uniq.insert(cur);
				level[cur] = lvl;
				cnt[lvl]++;
			}	
		
			if(lvl + 1 == SZ(r[i]))
				del.PB(i);
		}
		
		for(int i : del)
			poses.erase(i);
		lvl++;
	}
	Fenwick F;
	F.init(lvl);
	FOR(lv, 0, lvl)
		F.upd(lv, sub(binpow(2, cnt[lv]), 1));
	
	int ans = m + 1;
	FOR(i, 0, m)
	{
		int val = r[n][i];
		int lv = level[val];
		if(lv == -1)
		{
			ans = add(ans, F.query(lvl - 1));
			continue;
		}
		F.upd(lv, sub(1, binpow(2, cnt[lv])));
		cnt[lv]--;
		F.upd(lv, sub(binpow(2, cnt[lv]), 1));
		
		ans = add(ans, F.query(lv));
	}
	cout << ans << "\n";
}



int main()
{
    ios::sync_with_stdio(0); 
    cin.tie(0);
	
	int n, m;
	while(cin >> n >> m)
		solve(n, m);




	
	
	return 0;
}