import java.util.*;

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];
    for(int a=0; a<M; a++) {
      X[a] = 0;
    }
    int K;
    int count =0;
    
    for(int i=0; i<N; i++) {
      K = sc.nextInt();
      int A;
      for(int j=0; j<K; j++) {
        A = sc.nextInt();
        X[A-1]++;
      }
    }
    for(int k=0; k<M; k++) {
      if(X[k] == N) {
        count++;
      }
    }
    System.out.println(count);
  }
}
/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