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[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	}
} 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[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	} 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[] counts = new int[m]; counts new int[m] m for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		} {
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		} int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			} int i2 = 0; int i2 = 0; i2 0 i2 < k i2 k i2++ i2++ i2 {
				int a = sc.nextInt();
				counts[a - 1]++;
			} {
				int a = sc.nextInt();
				counts[a - 1]++;
			} int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc counts[a - 1]++ counts[a - 1] counts a - 1 a 1 int count = 0; count 0 for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		} int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
			if(counts[i] == n){
				count++;
			}
		} {
			if(counts[i] == n){
				count++;
			}
		} if(counts[i] == n){
				count++;
			} counts[i] == n counts[i] counts i n {
				count++;
			} count++ count System.out.println(count) System.out.println System.out System System.out count 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[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	}
} 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[] counts = new int[m];
		for(int i = 0; i < n; i++){
			int k = sc.nextInt();
			for(int i2 = 0; i2 < k; i2++){
				int a = sc.nextInt();
				counts[a - 1]++;
			}
		}
		int count = 0;
		for(int i = 0; i < m; i++){
			if(counts[i] == n){
				count++;
			}
		}
		System.out.println(count);
	}
}
