import java.util.*;
 
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();
        int n = sc.nextInt();
        sc.nextLine();
        int number[] = new int[30];
 
        for(int i = 0;i<m;i++){
            int tmp = sc.nextInt();
            for(int j = 0;j<tmp;j++){
                number[sc.nextInt()-1]++;
            }
            if(i != n-1){
                sc.nextLine();
            }
        }
        int count = 0;
        for(int i = 0;i<n;i++){
            if(number[i] == m){
                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