import java.util.Arrays;
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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }
} import java.util.Arrays; Arrays java.util 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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[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[] food = new int[m+1]; food new int[m+1] m+1 m 1 Arrays.fill(food, 0) Arrays.fill Arrays food 0 for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 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 a = sc.nextInt();
                food[a] += 1;
            }
        } {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        } int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            } int j = 0; int j = 0; j 0 j < k j k j++ j++ j {
                int a = sc.nextInt();
                food[a] += 1;
            } {
                int a = sc.nextInt();
                food[a] += 1;
            } int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc food[a] += 1 food[a] food a 1 int ans = 0; ans 0 for (int i = 0; i <= m; i++) {
            if (food[i] == n) {
                ans++;
            }
        } int i = 0; int i = 0; i 0 i <= m i m i++ i++ i {
            if (food[i] == n) {
                ans++;
            }
        } {
            if (food[i] == n) {
                ans++;
            }
        } if (food[i] == n) {
                ans++;
            } food[i] == n food[i] food 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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }
} Main
import java.util.Arrays;
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[] food = new int[m+1];
        Arrays.fill(food, 0);
        for (int i = 0; i < n; i++) {
            int k = sc.nextInt();
            for (int j = 0; j < k; j++) {
                int a = sc.nextInt();
                food[a] += 1;
            }
        }
        int ans = 0;
        for (int i = 0; i <= m; i++) {
            if (food[i] == n) {
                ans++;
            }
        }
        System.out.println(ans);
    }
}