import java.util.Scanner;
class Main{
  public static void main(String args[]){
    Scanner scan=new Scanner(System.in);
    int n=scan.nextInt();
    int m=scan.nextInt();
    int like[]=new int[m];
    int k;
    
    //reset
    for(int j=0;j<m;j++){
      like[j]=0;
    }
    for(int i=0;i<n;i++){
      k=scan.nextInt();
      for(int j=0;j<k;j++){
        like[scan.nextInt()-1]+=1;
      }
    }
    
    int count=0;
    for(int j=0;j<m;j++){
      if(like[j]==n) count+=1;
    }
    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