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 C# (Mono 4.6.2.0) (judge verdict: Time Limit Exceeded)

using static System.Console;
using static System.Convert;

class Program
{
    static void Main(string[] args)
    {
        var input = ReadLine().Split(' ');
        var max = ToInt32(input[0]);
        var num = ToInt32(input[1]);
        var result = 0;
        for(var i = 0; i <= max; i++)
        {
            for(var j = 0; j <= max; j++)
            {
                if (i < j) break;
                for(var h = 0; h <= max; h++)
                {
                    if (j < h) break;
                    if (i + j + h == num)
                    {
                        if (i == j && j == h && h == i) result++;
                        else if (i == j || j == h || h == i) result += 3;
                        else result += 6;
                    }
                }
            }
        }

        WriteLine(result);
    }
}