import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    }
} Main public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    } main {
        Main main = new Main();
        main.solve();
    } Main main = new Main(); main new Main() main.solve() main.solve main String[] args args public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    } solve {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    } Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in))); scan new Scanner(new BufferedReader(new InputStreamReader(System.in))) int N = scan.nextInt(); N scan.nextInt() scan.nextInt scan int M = scan.nextInt(); M scan.nextInt() scan.nextInt scan int[] counter = new int[M]; counter new int[M] M for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        } {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        } int K = scan.nextInt(); K scan.nextInt() scan.nextInt scan for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            } int j = 0; int j = 0; j 0 j < K j K j++ j++ j {
                int a = scan.nextInt();
                counter[a-1] += 1;
            } {
                int a = scan.nextInt();
                counter[a-1] += 1;
            } int a = scan.nextInt(); a scan.nextInt() scan.nextInt scan counter[a-1] += 1 counter[a-1] counter a-1 a 1 1 int answer = 0; answer 0 for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        } int i = 0; int i = 0; i 0 i < M i M i++ i++ i {
            if (counter[i] == N) {
                answer += 1;
            }
        } {
            if (counter[i] == N) {
                answer += 1;
            }
        } if (counter[i] == N) {
                answer += 1;
            } counter[i] == N counter[i] counter i N {
                answer += 1;
            } answer += 1 answer 1 System.out.println(answer) System.out.println System.out System System.out answer public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve();
    }
    public void solve() {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int N = scan.nextInt();
        int M = scan.nextInt();
        int[] counter = new int[M];
        for (int i = 0; i < N; i++) {
            int K = scan.nextInt();
            for (int j = 0; j < K; j++) {
                int a = scan.nextInt();
                counter[a-1] += 1;
            }
        }
        int answer = 0;
        for (int i = 0; i < M; i++) {
            if (counter[i] == N) {
                answer += 1;
            }
        }
        System.out.println(answer);
    }
}
