import java.util.Arrays;
import java.util.Scanner;

public class Main{
	static long mod = 1000000007;
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] eat = new int[M];
		Arrays.fill(eat, 0);
		for(int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for(int j = 0; j < K; j++) {
				int A = sc.nextInt() - 1;
				eat[A]++;
			}
		}
		int ans = 0;
		for(int i = 0; i < M; i++) if(eat[i] == N) ans++;
		System.out.println(ans);
	}
}

/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