Problem:
Score : 200 points

Problem Statement

You are given two integers K and S.

Three variable X, Y and Z takes integer values satisfying 0≤X,Y,Z≤K.

How many different assignments of values to X, Y and Z are there such that X + Y + Z = S?

Constraints

2≤K≤2500

0≤S≤3K

K and S are integers.

Input

The input is given from Standard Input in the following format:

K S

Output

Print the number of the triples of X, Y and Z that satisfy the condition.

Sample Input 1

2 2

Sample Output 1

6

There are six triples of X, Y and Z that satisfy the condition:

X = 0, Y = 0, Z = 2

X = 0, Y = 2, Z = 0

X = 2, Y = 0, Z = 0

X = 0, Y = 1, Z = 1

X = 1, Y = 0, Z = 1

X = 1, Y = 1, Z = 0

Sample Input 2

5 15

Sample Output 2

1

The maximum value of X + Y + Z is 15, achieved by one triple of X, Y and Z.

Solution in PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
fscanf(STDIN,'%d%d',$K,$S);
$c=0;
for ($x=0; $x <=ceil($K/3) ; $x++) {
  // code...
  for ($y=$x; $y <=ceil($K/2) ; $y++) {
    // code...
    for ($z=$y; $z <=$K ; $z++) {
      // code...
      if($x+$y+$z==$S){
        if($x!=$y and $y!=$z){
          $c+=6;
        }elseif($x!=$y or $y!=$z){
          $c+=3;
        }else{
          $c++;
        }
        break;
      }
    }
  }
}
echo $c;
echo "\n";

 ?>