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 Pascal (FPC 3.0.4) (judge verdict: Time Limit Exceeded)

program taskF;
var
    k, s, x, y, z : longint;
    ans : longint;
    
begin
    readln(k,s);
    ans := 0;
    for x := 0 to k do
    begin
        for y := 0 to k do
        begin
            for z := 0 to k do
            begin
                if (x + y + z = s) then
                begin
                    ans := ans + 1;
                end;
            end;
        end;
    end;
    writeln(ans);
end.