import java.util.*;
 
class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
      
      	int hito = sc.nextInt();
      	int menu = sc.nextInt();
      	int mesi[] = new int[menu+1];
      
      for(int i = 0; i < hito; i++){
        int a = sc.nextInt();
      	for(int j = 0; j < a;j++){
        	mesi[sc.nextInt()] += 1;
        }
      }
		int cnt = 0;
		for(int i = 1; i <= menu ; i++){
          if(mesi[i]==hito){cnt++;}
        }
      	System.out.print(cnt);


    }
}
/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