import java.util.*;
public class Main {
	public static void main(String[]args) {
		Scanner sc=new Scanner(System.in);
      int n=sc.nextInt();int m=sc.nextInt();
      int[]a=new int[m];
      for(int i=0;i<n;i++){
      	int b=sc.nextInt();
        for(int j=0;j<b;j++){
        	a[sc.nextInt()-1]++;
        }
      }
      int count=0;
      for(int i=0;i<m;i++)if(a[i]==n)count++;
      System.out.println(count);
	}
}

/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