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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)


import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		//		new Main().solveB();
		new Main().solveB2();
		//		new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int lineAB = 0;
		int lineBC = 0;

		try {
			scanner = new Scanner(System.in);
			lineAB = scanner.nextInt();
			lineBC = scanner.nextInt();

			if (lineBC % lineAB == 0) {
				System.out.println(lineAB + lineBC);
			} else {
				System.out.println(lineBC - lineAB);
			}

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB2() {
		Scanner scanner = null;
		int numN = 0;
		int numM = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			numM = scanner.nextInt();

			Map<Integer, Integer> wkMap = new HashMap<Integer, Integer>();

			for (int i = 0; i < numN; i++) {

				int numK = scanner.nextInt();
				for (int j = 0; j < numK; j++) {
					int foodNum = scanner.nextInt();
					if (!wkMap.containsKey(foodNum)) {
						wkMap.put(foodNum, 0);
					}
					int result = wkMap.get(foodNum);
					result++;
					wkMap.put(foodNum, result);
				}
			}

			int count = 0;
			for (Integer wkInt : wkMap.values()) {
				if (wkInt == numN) {
					count++;
				}
			}
			System.out.println(count);

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int nNin = 0;
		int mSyurui = 0;

		try {
			scanner = new Scanner(System.in);
			String line1 = scanner.nextLine();
			String[] wkStr1 = line1.split(" ");
			nNin = Integer.parseInt(wkStr1[0]);
			mSyurui = Integer.parseInt(wkStr1[1]);

			List<List<Integer>> wkList = new ArrayList<List<Integer>>();

			for (int i = 0; i < nNin; i++) {
				String wk = scanner.nextLine();
				String[] wkStr = wk.split(" ");
				List<Integer> wkInnerList = new ArrayList<Integer>();
				for (int j = 1; j < wkStr.length; j++) {
					wkInnerList.add(Integer.parseInt(wkStr[j]));
				}
				wkList.add(wkInnerList);
			}

			int result = 0;
			List<Integer> alreadyFinishList = new ArrayList<Integer>();
			for (int i = 0; i < wkList.size(); i++) {
				List<Integer> wkInnerList = wkList.get(i);
				for (int i2 = 0; i2 < wkInnerList.size(); i2++) {
					int syokuNum = wkInnerList.get(i2);
					if (alreadyFinishList.contains(syokuNum)) {
						continue;
					}
					if (isContain(nNin, wkList, i, syokuNum)) {
						result++;
					}
					alreadyFinishList.add(syokuNum);
				}

			}
			System.out.println(result);

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private boolean isContain(int nNin, List<List<Integer>> wkList, int i, int syokuNum) {
		int result = 0;
		for (int j = 0; j < nNin; j++) {
			if (i == j || j >= wkList.size()) {
				continue;
			}

			List<Integer> wkSarchList = wkList.get(j);
			if (wkSarchList.contains(syokuNum)) {
				result++;
			}

		}
		return result == nNin - 1;
	}

	public long maximuKouyakuNArgs(long currentKouyaku, long[] nums, int start) {
		long res = currentKouyaku;
		if (start < nums.length) {
			res = maximumKouyaku2Args(nums[start], currentKouyaku);
			return maximuKouyakuNArgs(res, nums, start + 1);
		} else {
			return res;
		}
	}

	public long maximumKouyaku2Args(long num1, long num2) {
		try {
			long wkVal1;
			long wkVal2;
			if (num1 < num2) {
				wkVal1 = num2;
				wkVal2 = num1;
			} else {
				wkVal1 = num1;
				wkVal2 = num2;
			}
			long res = wkVal1 % wkVal2;
			if (res != 0) {
				return maximumKouyaku2Args(wkVal2, res);
			} else {
				return wkVal2;
			}

		} catch (Exception e) {
			System.out.println("num1 : " + num1 + " / num2:" + num2);
			e.printStackTrace();
			return -1;
		}

	}

	private void solveC() {
		Scanner scanner = null;
		int monsterNum = 0;

		try {
			scanner = new Scanner(System.in);
			monsterNum = scanner.nextInt();
			long[] monsters = new long[monsterNum];
			for (int i = 0; i < monsterNum; i++) {
				monsters[i] = scanner.nextInt();
			}
			//
			//			Arrays.sort(monsters);
			//			int minHP = Integer.MAX_VALUE;
			//			if (monsters[0] == monsters[monsters.length - 1]) {
			//				System.out.println(monsters[0]);
			//				return;
			//			} else {
			//				minHP = getMinHP(monsters, minHP);
			//			}
			System.out.println(maximuKouyakuNArgs(monsters[0], monsters, 0));

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private Map<Integer, Integer> wkHP = new HashMap<Integer, Integer>();

	private int getMinHP(int[] monsters, int minHP) {
		int resultHP = minHP;
		try {
			if (wkHP.get(minHP) != null) {
				return wkHP.get(minHP);
			}
			for (int i = 0; i < monsters.length; i++) {
				if (i == 0) {
					continue;
				}
				if (monsters[i] % monsters[0] == 0) {
					resultHP = Math.min(monsters[0], resultHP);
				} else {
					resultHP = Math.min(monsters[i] % monsters[0], resultHP);
				}
			}
			if (resultHP > 2) {
				resultHP = getMinHP(monsters, resultHP);
			}
			wkHP.put(minHP, resultHP);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return resultHP;

	}

	private void solveD() {
		Scanner scanner = null;
		int lineAB = 0;
		int lineBC = 0;
		int lineCA = 0;

		try {
			scanner = new Scanner(System.in);
			lineAB = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
}