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: Time Limit Exceeded)

function Main(input) {
  var inputs = input.split(' ');
  var K = Number(inputs[0]);
  var S = Number(inputs[1]);
  var count = 0;
  for(var X = 0; X <= K; X++) {
    for(var Y = 0; Y <= K; Y++) {
      for(var Z = 0; Z <= K; Z++) {
        if (X + Y + Z === S) {
          count++;
        }
      }
    }
  }
  console.log(count);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));