import java.io.*;
import java.util.Scanner;


public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();
		int m = sc.nextInt();
		
		int[] cnt = new int[m];
		for (int i = 0; i < n; i++) {
			int k = sc.nextInt();
			for (int j = 0; j < k; j++) {
				int a = sc.nextInt() - 1;
				cnt[a]++;
			}
		}

		int ans = 0;
		for (int i = 0; i < m; i++) {
			if (cnt[i] == n) {
				ans++;
			}
		}

		pr.println(ans);
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);
			
		solve();
			
		pr.close();
		sc.close();
	}

	static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz