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[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }

} import java.util.Scanner; Scanner 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[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }

} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int m = sc.nextInt(); m sc.nextInt() sc.nextInt sc int[] a = new int[m]; a new int[m] m for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        } {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        } int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            } int j = 0; int j = 0; j 0 j < k j k j++ j++ j {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            } {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            } int tmp = sc.nextInt(); tmp sc.nextInt() sc.nextInt sc a[tmp - 1]++ a[tmp - 1] a tmp - 1 tmp 1 sc.close() sc.close sc int ans = 0; ans 0 for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        } int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
            if (a[i] == n) {
                ans++;
            }
        } {
            if (a[i] == n) {
                ans++;
            }
        } if (a[i] == n) {
                ans++;
            } a[i] == n a[i] a i n {
                ans++;
            } ans++ ans System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }

} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }

} Main
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[] a = new int[m];
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int tmp = sc.nextInt();
                a[tmp - 1]++;
            }
        }
        sc.close();

        int ans = 0;
        for (int i = 0; i < m; i++) {
            if (a[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }

}
