import java.util.Scanner;
public class Main {
	
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		int x[]=new int[M];
		int sum=0;
		
		for(int i=0;i<N;i++) {
			int K=sc.nextInt();
		
			for(int j=1;j<=K;j++) {
				int A=sc.nextInt();
				x[A-1]++;
			}
		}
		for(int l=0;l<M;l++) {
			if(x[l]==N) {
				sum++;
			}
		}
		System.out.print(sum);
       
	}

}
/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