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[] Ai = new int[M];
   int K =0;
   int tmp = 0;
   for(int i=0;i<N;i++)
   {
     K = sc.nextInt();
     for(int l = 0;l<K;l++)
     {
       tmp = sc.nextInt();
       Ai[tmp-1]++;
     }
   }
   
   int count = 0;
   for(int i = 0;i<M;i++)
   {
     if(Ai[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