Problem:
Score : 200 points

Problem Statement

Katsusando loves omelette rice.

Besides, he loves crème brûlée, tenderloin steak and so on, and believes that these foods are all loved by everyone.

To prove that hypothesis, he conducted a survey on M kinds of foods and asked N people whether they like these foods or not.

The i-th person answered that he/she only likes the A_{i1}-th, A_{i2}-th, ..., A_{iK_i}-th food.

Find the number of the foods liked by all the N people.

Constraints

All values in input are integers.

1 \leq N, M \leq 30

1 \leq K_i \leq M

1 \leq A_{ij} \leq M

For each i (1 \leq i \leq N), A_{i1}, A_{i2}, ..., A_{iK_i} are distinct.

Constraints

Input is given from Standard Input in the following format:

N M
K_1 A_{11} A_{12} ... A_{1K_1}
K_2 A_{21} A_{22} ... A_{2K_2}
:
K_N A_{N1} A_{N2} ... A_{NK_N}

Output

Print the number of the foods liked by all the N people.

Sample Input 1

3 4
2 1 3
3 1 2 3
2 3 2

Sample Output 1

1

As only the third food is liked by all the three people, 1 should be printed.

Sample Input 2

5 5
4 2 3 4 5
4 1 3 4 5
4 1 2 4 5
4 1 2 3 5
4 1 2 3 4

Sample Output 2

0

Katsusando's hypothesis turned out to be wrong.

Sample Input 3

1 30
3 5 10 30

Sample Output 3

3

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;


namespace AtCoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Anser(new ConsoleInput(Console.In, ' '));
        }

        public void Anser(ConsoleInput Input)
        {
            var inputData = Input.ReadIntArray(2);
            var favoriteData = new List<int>();
            
            for (int i = 0; i < inputData[0]; i++)
            {
                favoriteData.AddRange(Input.ReadLine.Split(' ').Select(x => Convert.ToInt32(x)).Distinct().ToList<int>());
            }

            var anserCount = 0;

            for (int i = 1; i <= inputData[1]; i++)
            {
                var favo = favoriteData.Count(x => x == i);

                if (favo == inputData[0])
                    anserCount++;
            }

            Console.WriteLine(anserCount);
        }
    }

    public class ConsoleInput
    {
        private readonly System.IO.TextReader Stream;
        private char Separator = ' ';
        private Queue<string> InputStream;

        public ConsoleInput(System.IO.TextReader Stream, char Separator = ' ')
        {
            this.Separator = Separator;
            this.Stream = Stream;
            InputStream = new Queue<string>();
        }

        public string Read
        {
            get
            {
                if (InputStream.Count != 0)
                {
                    return InputStream.Dequeue();
                }

                string[] splitStrs = Stream.ReadLine().Split(Separator);

                for (int i = 0; i < splitStrs.Length; ++i)
                {
                    InputStream.Enqueue(splitStrs[i]);
                }

                return InputStream.Dequeue();
            }
        }

        public string ReadLine { get { return Stream.ReadLine(); } }
        public int ReadInt { get { return int.Parse(Read); }}
        public long ReadLong { get { return long.Parse(Read); }}
        public double ReadDouble { get { return double.Parse(Read); }}

        public string[] ReadStrArray(long N) 
        { 
            var inputStrArray = new string[N];
            for (long i = 0; i < N; ++i)
            {
                inputStrArray[i] = Read;
            } 
            
            return inputStrArray;
        }

        public int[] ReadIntArray(long N) 
        { 
            var inputIntArray = new int[N];
            for (long i = 0; i < N; ++i)
            {
                inputIntArray[i] = ReadInt;
            }
           
            return inputIntArray;
        }

        public long[] ReadLongArray(long N) 
        { 
            var inputLongArray = new long[N];
            for (long i = 0; i < N; ++i)
            {
                inputLongArray[i] = ReadLong;
            }
            
            return inputLongArray;
        }
    }
}