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)

// https://atcoder.jp/contests/abc051/tasks/abc051_b
"use strict";
function Main(input) {
  // const [K, S] = input.split(" ").map(Number);
  const params = input.split(" ").map(Number);
  const K = params[0];
  const S = params[1];

  let count = 0;
  for (let x = 0; x <= K; x++) {
    if (x > S) break;
    for (let y = 0; y <= K; y++) {
      if (x + y > S) break;
      for (let z = 0; z <= K; z++) {
        if (x + y + z > S) {
          break;
        }
        if (x + y + z === S) {
          count++;
          break;
        }
      }
    }
  }
  console.log(count);
}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));