import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int N = sc.nextInt();
        int M = sc.nextInt();
        int[] likeNum = new int[M];
        for (int i=0;i<M;i++){
            likeNum[i] = 0;
        }

        for(int i=0;i<N;i++){
            int K = sc.nextInt();
            for(int j=0;j<K;j++){
                likeNum[sc.nextInt() - 1]++;
            }
        }

        int result=0;
        for(int i=0;i<M;i++){
            if(likeNum[i] == N){
                result++;
            }
        }
        System.out.println(result);

    }
}

/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