Problem:
How many ways?

Write a program which identifies the number of combinations of three integers which satisfy the following conditions:

You should select three distinct integers from 1 to n.

A total sum of the three integers is x.

For example, there are two combinations for n = 5 and x = 9.

1 + 3 + 5 = 9

2 + 3 + 4 = 9

Input

The input consists of multiple datasets. For each dataset, two integers n and x are given in a line.

The input ends with two zeros for n and x respectively. Your program should not process for these terminal symbols.

Constraints

3 ≤ n ≤ 100

0 ≤ x ≤ 300

Output

For each dataset, print the number of combinations in a line.

Sample Input

5 9
0 0

Sample Output

2

Note

      解説

Solution in Scala (judge verdict: Accepted)

import scala.io.StdIn.readLine
import scala.math.{max,min}

object Main extends App {

  var m = readLine.split(" ").map(_.toInt)
  while( (m(0),m(1)) != (0,0) ){
    val Array(n,x) = m
    println( ( 1 until min(n-1,x/3) ).foldLeft(0) { (sum,i) => sum + (max(i+1,x-i-n) until min(n,(x-i+1)/2)).length })

    m = readLine.split(" ").map(_.toInt)
  }
}