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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
  # 2WAがとれず。。。。。

  
  $n = intVal(trim(fgets(STDIN)));
  $s = array_map("intVal", explode(" ", trim(fgets(STDIN))));
  $color = 0;
  $ans = 1;
  $MOD = 1000000007;
  $cur = [-1, -1, -1];

  if($s[0] != 0){
    echo 0 . PHP_EOL;
    exit();
  }
  foreach($s as $c){
    if($c == 0){
      $cur[$color] = 0;
      $color += 1;
      $ans %= $MOD;
    }else{
      $x = 0;
      foreach($cur as $curn){
        if($curn == $c-1){
          $x += 1;
        }
      }
      if($x == 0){
        echo 0 . PHP_EOL;
        exit();
      }
      $ans *= $x;
      $ans %= $MOD;
      $idx = array_search($c-1, $cur);
      $cur[$idx] += 1;
    }
  }

  if($color == 1){
    $ans *= 3;
  }elseif($color == 2){
    $ans *= 6;
  }
  $ans %= $MOD;
  echo $ans . PHP_EOL;
?>