import java.util.Scanner;
import java.util.ArrayList;
 
public class Main {
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int N = Integer.parseInt(scanner.next());
    int M = Integer.parseInt(scanner.next());
    
    ArrayList<Integer> answer = new ArrayList<Integer>();
    for(int i=0;i<=M;i++){
      answer.add(0);
    }
    
    for(int i=0;i<N;i++){
      int A = Integer.parseInt(scanner.next());
      for(int j=0;j<A;j++){
      	int input = Integer.parseInt(scanner.next());
      	int pre = answer.get(input);
       	answer.set(input, pre + 1);
      }
    }
    int ans = 0;
    for(int i=1;i<=M;i++){
      if(answer.get(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