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)

object Main extends App {
	
	override def main(args:Array[String]) = {
		val sc = new java.util.Scanner(System.in)
		
		Iterator.continually(new DataSet(sc.nextInt,sc.nextInt)).
		takeWhile(_.isContinue).foreach(d => println(d.solve))
	}
	
	case class DataSet(val n:Int, val x:Int){
		val isContinue = !( n == 0 && x == 0)

		def solve = {
			var sum:Int = 0
			// i < j < k ??§????????????????????????
			// i ??? x / 3 ????¶??????????
			
			// ??\???(i , j , k) = x ???????????????i????????°??¨?????????
			for(i <- ( 1 to x / 3)){
				 
				// k ?????¨??????????????§?????? k = x - i - j ??§
				// j = i ??¨????????? k = x - i - i - 1???
				// ????????§??¶?´??????¶??¨?????? k ??? n????¶??????????
				val max_k = math.min(x - i*2 - 1, n) 
				
				// j ???????°???¨????????????k????????§????????§
				val min_j = x - i - max_k
				
				if(max_k > min_j){
					// (i , min_j , max_k)
					// (i , min_j + 1 , max_k - 1)
					// (i , min_j + 2 , max_k - 2)
					// ?????????
					// (i , min_j + z , max_k - z)
					// z = (max_k - min_j) / 2
					val z = (max_k - min_j + 1) / 2
					val pattern_jk = z 
					sum += pattern_jk
				}
			}
			sum
		}
	}
}