import java.util.*;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		}
		System.out.println(count);
	}

} import java.util.*; util.* java public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		}
		System.out.println(count);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		}
		System.out.println(count);
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[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 M = sc.nextInt(); M sc.nextInt() sc.nextInt sc int[] b = new int[M]; b new int[M] M for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		} 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()-1;
				b[a]++;
			}
		} {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		} int K = sc.nextInt(); K sc.nextInt() sc.nextInt sc for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			} int j = 0; int j = 0; j 0 j < K j K j++ j++ j {
				int a = sc.nextInt()-1;
				b[a]++;
			} {
				int a = sc.nextInt()-1;
				b[a]++;
			} int a = sc.nextInt()-1; a sc.nextInt()-1 sc.nextInt() sc.nextInt sc 1 b[a]++ b[a] b a int count = 0; count 0 for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		} int i = 0; int i = 0; i 0 i < M i M i++ i++ i {
			if (b[i] == N) count++;
		} {
			if (b[i] == N) count++;
		} if (b[i] == N) count++; b[i] == N b[i] b i N 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(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[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(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		}
		System.out.println(count);
	}

} Main
import java.util.*;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt(), M = sc.nextInt();
		int[] b = new int[M];
		for (int i = 0; i < N; i++) {
			int K = sc.nextInt();
			for (int j = 0; j < K; j++) {
				int a = sc.nextInt()-1;
				b[a]++;
			}
		}
		int count = 0;
		for (int i = 0; i < M; i++) {
			if (b[i] == N) count++;
		}
		System.out.println(count);
	}

}