import java.util.Arrays;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt(),m = sc.nextInt();
		int a = 0;
		int[] mkind = new int[m+1];
		for(int i = 0;i < n;i ++) {
			int k = sc.nextInt();
			for(int j = 0;j < k;j++) {
				a = sc.nextInt();
				mkind[a]++;
			}
		}
		//System.out.println(Arrays.toString(mkind));
		int sum = 0;
		for(int i = 0;i < m+1;i ++) {
			if(mkind[i] == n) sum ++;
			//System.out.println(mkind[i]);
		}
		System.out.println(sum);
	}
}
/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