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 Ruby (2.3.3) (judge verdict: Wrong Answer)

if __FILE__==$0
	reads_i=lambda{|s,d|s.strip.split(d).map(&:to_i)}
	data=reads_i[gets," "]
	k=data[0]
	s=data[1]
	cnt=0
	for x in 0..s+1
		for y in 0..s+1
			for z in 0..s+1
				if x+y+z==s then cnt+=1 end
			end
		end
	end
	p cnt
end