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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

"use strict";

const main = arg => {
    arg = arg.trim().split("\n");
    const K = parseInt(arg[0].split(" ")[0]);
    const S = parseInt(arg[0].split(" ")[1]);
    
    let answer = 0;
    
    for(let i=0; i<=K; i++) {
        for(let j=0; j<=K; j++) {
            let X = i;
            let Y = j;
            
            if(i + j > K) continue;
            
            if(K - (i+j) <= K) {
                // console.log("X:" + X);
                // console.log("Y:" + Y);
                
                answer++;
            }
        }
    }
    
    console.log(answer);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));