import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    int M = scanner.nextInt();
    int[] freq = new int[M];
    for (int i = 0; i < N; i++) {
      int K = scanner.nextInt();
      for (int j = 0; j < K; j++) {
        int a = scanner.nextInt() - 1;
        freq[a]++;
      }
    }
    int tot = 0;
    for (int f : freq) if (f == N) tot++;
    System.out.println(tot);
  }
}

/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