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: Accepted)

<?php
    list($max, $sum) = explode(" ", trim(fgets(STDIN)));
    
    $count = 0;
    for($i=0;$i<=$max;$i++){
        for($j=0;$j<=$max;$j++){
            $m = $sum - $i - $j;
            if($m>=0&&$m<=$max){
//                echo $i," ",$j," ",$m,PHP_EOL;
                $count++;
            }
        }
    }

    echo $count;
 
?>