import java.util.Scanner;

public class Main {

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		int M = Integer.parseInt(sc.nextLine().trim());
		
		int[] i = new int[M];
		
		for(int j = 0; j < i.length; j++) {
			i[j] = 0;
		}
		
		for(int k = 0; k < N; k++) {
			String s = sc.nextLine();
			String[] split = s.split(" ");
			
			for(int l = 1; l < split.length; l++) {
				int a = Integer.parseInt(split[l])-1;
				
				i[a]++;
			}
		}
		
		int res = 0;
		
		for(int n = 0; n <i.length; n++) {
			if(i[n] == N) {
				res++;
			}
		}
		System.out.println(res);
	}
}
/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