import java.util.*;

public class Main{
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt(), M = sc.nextInt(), total=0;
    int A[] = new int[M];
    for(int i=0; i<M; i++) {
      A[i] = 0;
    }
    
    for(int j=0; j<N; j++) {
      int L = sc.nextInt();
      for(int k=0; k<L; k++) {
        int f = sc.nextInt();
        A[f-1] ++;
      }
    }
    
    for(int l=0; l<M; l++) {
      if(A[l] == N) {
        total++;
      }
    }
    System.out.println(total);
  }
}
/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