Problem:
Score: 100 points

Problem Statement

In this problem, a date is written as Y-M-D. For example, 2019-11-30 means November 30, 2019.

Integers M_1, D_1, M_2, and D_2 will be given as input.

It is known that the date 2019-M_2-D_2 follows 2019-M_1-D_1.

Determine whether the date 2019-M_1-D_1 is the last day of a month.

Constraints

Both 2019-M_1-D_1 and 2019-M_2-D_2 are valid dates in the Gregorian calendar.

The date 2019-M_2-D_2 follows 2019-M_1-D_1.

Input

Input is given from Standard Input in the following format:

M_1 D_1
M_2 D_2

Output

If the date 2019-M_1-D_1 is the last day of a month, print 1; otherwise, print 0.

Sample Input 1

11 16
11 17

Sample Output 1

0

November 16 is not the last day of a month.

Sample Input 2

11 30
12 1

Sample Output 2

1

November 30 is the last day of November.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)


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

public class Main {

    public static void main(String[] args) {
        new Main().run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        String S = scanner.next();
        Map<String, Integer> map = new HashMap<>();
        Map<Character, Boolean> flg = new HashMap<>();

        for (int i = 0; i < S.length() - 2; i++) {
            if(flg.containsKey(S.charAt(i))){
                continue;
            }else{
                flg.put(S.charAt(i), true);
            }
            for (int j = i + 1; j < S.length() - 1; j++) {
                for (int k = j + 1; k < S.length(); k++) {
                    map.put(S.charAt(i) + String.valueOf(S.charAt(j)) + S.charAt(k), 1);

                }
            }
        }
        System.out.println(map.size());
    }
}