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 t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[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 A[] = new int[M];
		for (int i=0;i<N;i++) {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[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 A[] = new int[M];
		for (int i=0;i<N;i++) {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[i]==N) {
				count ++;
			}
		}
		System.out.println(count);
	} 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 t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[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 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 t = sc.nextInt();
				A[t-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 t = sc.nextInt();
				A[t-1]++;
			}
		} {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		} int K =sc.nextInt(); K sc.nextInt() sc.nextInt sc for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			} int j =0; int j =0; j 0 j<K j K j++ j++ j {
				int t = sc.nextInt();
				A[t-1]++;
			} {
				int t = sc.nextInt();
				A[t-1]++;
			} int t = sc.nextInt(); t sc.nextInt() sc.nextInt sc A[t-1]++ A[t-1] A t-1 t 1 int count=0; count 0 for (int i=0;i<M;i++) {
			if (A[i]==N) {
				count ++;
			}
		} int i=0; int i=0; i 0 i<M i M i++ i++ i {
			if (A[i]==N) {
				count ++;
			}
		} {
			if (A[i]==N) {
				count ++;
			}
		} if (A[i]==N) {
				count ++;
			} A[i]==N A[i] A 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 A[] = new int[M];
		for (int i=0;i<N;i++) {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[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 A[] = new int[M];
		for (int i=0;i<N;i++) {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[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 A[] = new int[M];
		for (int i=0;i<N;i++) {
			int K =sc.nextInt();
			for (int j =0;j<K;j++) {
				int t = sc.nextInt();
				A[t-1]++;
			}
		}
		int count=0;
		for (int i=0;i<M;i++) {
			if (A[i]==N) {
				count ++;
			}
		}
		System.out.println(count);
	}
}
