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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program ABC_051_B_SumofThreeIntegers
   implicit none
   integer X, Y, Z, K, S, countN
   read(*, *) K, S
   countN = 0
   do X = 0, K
       do Y = 0, K
	      Z = S - (X + Y)
		  if(X + Y + Z == S .and. Z >=0 .and. Z <= K ) then
			  countN = countN + 1
		  end if
	   end do
   end do
   write(*, *) countN
end program ABC_051_B_SumofThreeIntegers