#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <stack>
#include <numeric>




typedef long long ll;
#define PI 3.14159265359
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define _GLIBCXX_DEBAC
#include <functional>
/*map<Keyの型, Valueの型> 変数名;
queue<型> 変数名;
priority_queue<型> 変数名;
priority_queue<型, vector<型>, greater<型>> 変数名;*/
//copy(v1.begin(), v1.end(), back_inserter(v2));
using namespace std;

ll gcd(ll a, ll b) {
	ll c;
	if (a < b) {
		c = a; a = b; b = c;
	}
	while (b != 0) {
		c = a % b; a = b; b = c;
	}
	return a;
}

ll lcm(ll a, ll b) {
	ll c;
	c = a * b / gcd(a, b);
	return c;
}

int sort_greater(int m,int n) {
	vector<int> a(m);
	for (int i = 0; i < m; i++) {
		cin >> a[i];
	}
	sort(a.begin(), a.end(),greater<int>());
	for (int i = 0; i < n; i++) {
		cout << a[i];
	}
		return 0;
}

int bubblesort(int a[], int n) {
	int sw = 0;
	bool flag = 1;
	for (int i = 0; flag; i++) {
		flag = 0;
		for (int j = n - 1; j >= i + 1; j--) {
			if (a[j] < a[j - 1]) {
				swap(a[j], a[j - 1]);
				flag = 1;
				sw += 1;
			}
		}
	}
	return sw;
}

int a_z()
{
	for (int i = 0; i <= ('Z' - 'A'); i++) {
		cout << (char)('A' + i);
	}
	return 0;
}

int selecttionsort(int a[], int n) {
	int t,sw = 0, minj;
	for (int i = 0; i < n - 1; i++) {
		minj = i;
		for (int j = 0; j < n - 1; j++) {
			if (a[j] < a[minj]) {
				minj = j;
			}
		}
		t = a[i]; a[i] = a[minj]; a[minj] = t;
		if (i != minj) sw += 1;

	}
	return sw;
}

bool is_prime(int x) {
	if (x <= 1) return false;
	for (int i = 2; i * i <= x; i++) {
		if (x % i == 0) return false;
	}
	return true;
}

const ll mod = 1000000007;
struct mint {
	ll x;
	mint(ll x = 0):x(x%mod){}
	mint& operator+=(const mint a) {
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator-=(const mint a) {
		if ((x += mod - a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator*=(const mint a) {
		(x *= a.x) %= mod;
		return *this;
	}
	mint operator+(const mint a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint a) const {
		mint res(*this);
		res -= a;
	}
	mint operator*(const mint a)const {
		mint res(*this);
		return res *= a;
	}
};

map<string, int> memo;

using P=pair<int, int>;




/*void dfs(int v, int p = -1) {
	for (int u : to[v]) {
		if (u == p) continue;
		ans[u] += ans[v];
		dfs(u, v);
	}
}*/

ll nCr(ll n, ll r) {
	ll a = 1;
	for (ll i = n; i > n - r; --i) {
		a = a * i;
	}
	for (ll i = 1; i < r + 1; ++i) {
		a = a / i;
	}
	return a;
}

void comb(vector<vector <long long int> >& v) {
	for (int i = 0; i < v.size(); i++) {
		v[i][0] = 1;
		v[i][i] = 1;
	}
	for (int k = 1; k < v.size(); k++) {
		for (int j = 1; j < k; j++) {
			v[k][j] = (v[k - 1][j - 1] + v[k - 1][j]);
		}
	}
}


int main() {
	/* ABC164-C
	ll n;
	cin >> n;
	map<string, ll> p;
	rep(i, n) {
		string s;
		cin >> s;
		p[s]++;
	}
	cout << p.count;*/

	
	 

	
	int n, m;
	cin >> n >> m;
	vector<int> a(m, 0);
	rep(i, n) {
		int k;
		cin >> k;
		rep(j, k) {
			int x; cin >> x; x--;
			a[x]++;
		}
	}
	int ans = 0;
	rep(i, m) {
		if (a[i] == n)ans++;
	}
	cout << ans;


	return 0;
}










Measured memory_bytes: 256