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 Scala (2.11.7) (judge verdict: Time Limit Exceeded)

import scala.io.StdIn


object Main extends App {
  val Array(k, s)  = StdIn.readLine.split(" ").map(_.toInt)

  def solve(k: Int, s: Int) : Int  = {
    var cnt = 0
    for(x <- 0 to k; y <- 0 to k; z <- 0 to k) {
      (x + y + z) match {
        case `s` => cnt += 1
        case _ => 0
      }
    }
    cnt
  }
  println(solve(k, s))

}