import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        
        int n = Integer.parseInt(sc.next());
        int m = Integer.parseInt(sc.next());
        
        int[] love = new int[m];
        int k, a;
        for(int i = 0; i < n; i++){
            k = Integer.parseInt(sc.next());
            for(int j = 0; j < k; j++){
                a = Integer.parseInt(sc.next());
                love[a-1]++;
            }
        }
        
        int count = 0;
        for(int i = 0; i < m; i++){
            if(love[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