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[] favorite = new int[m];
		for(int i = 0; i < n; i++) {
			int loopCount = sc.nextInt();
			for(int j = 0; j <loopCount; j++) {
				favorite[sc.nextInt() -1]++;
			}
		}
		int answer = 0;
		for(int i =0; i < m; i++) {
			if(favorite[i] == n) {
				answer++;
			}
		}

		System.out.println(answer);
	}

}
/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