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[] suki = new int[m];
		for(int i = 0; i < n; i ++) {
			int k = sc.nextInt();
			for(int j = 0; j < k; j ++) {
				suki[sc.nextInt() - 1] ++;
			}
		}
		sc.close();
		int count = 0;
		for(int i=0; i < m; i ++) {
			if(suki[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[] suki = new int[m];
		for(int i = 0; i < n; i ++) {
			int k = sc.nextInt();
			for(int j = 0; j < k; j ++) {
				suki[sc.nextInt() - 1] ++;
			}
		}
		sc.close();
		int count = 0;
		for(int i=0; i < m; i ++) {
			if(suki[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[] suki = new int[m];
		for(int i = 0; i < n; i ++) {
			int k = sc.nextInt();
			for(int j = 0; j < k; j ++) {
				suki[sc.nextInt() - 1] ++;
			}
		}
		sc.close();
		int count = 0;
		for(int i=0; i < m; i ++) {
			if(suki[i] == n) {
				count ++;
			}
		}
		System.out.println(count);

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

	}
}