import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    }

    public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}
 import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    }

    public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskB solver = new TaskB(); solver new TaskB() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String argds[] argds static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    } TaskB public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        } solve {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        } int n = in.nextInt(); n in.nextInt() in.nextInt in int m = in.nextInt(); m in.nextInt() in.nextInt in int[] cnt = new int[m + 1]; cnt new int[m + 1] m + 1 m 1 for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            } {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            } int k = in.nextInt(); k in.nextInt() in.nextInt in for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                } int j = 0; int j = 0; j 0 j < k j k j++ j++ j {
                    int a = in.nextInt();
                    cnt[a]++;
                } {
                    int a = in.nextInt();
                    cnt[a]++;
                } int a = in.nextInt(); a in.nextInt() in.nextInt in cnt[a]++ cnt[a] cnt a int ans = 0; ans 0 for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            } int i = 0; int i = 0; i 0 i < m + 1 i m + 1 m 1 i++ i++ i {
                if (cnt[i] == n) ans++;
            } {
                if (cnt[i] == n) ans++;
            } if (cnt[i] == n) ans++; cnt[i] == n cnt[i] cnt i n ans++ ans out.println(ans) out.println out ans int testNumber testNumber InputReader in in PrintWriter out out static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    } InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    }

    public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
} public class Main {
    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    }

    public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[] cnt = new int[m + 1];
            for (int i = 0; i < n; i++) {
                int k = in.nextInt();
                for (int j = 0; j < k; j++) {
                    int a = in.nextInt();
                    cnt[a]++;
                }
            }
            int ans = 0;
            for (int i = 0; i < m + 1; i++) {
                if (cnt[i] == n) ans++;
            }
            out.println(ans);
        }
    }

    public static void main(String argds[]) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}

