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)

var 
    k,s,cnt,i,j,b,z : longint;
begin
    readln(k,s);
    if (s / k = 3) and (s = 0 ) then
    begin
        writeln('1');
        halt;
    end;
    if k>s then k := s
    else if k = s then
    begin
        k := s-1;
        z := z + 1;
    end;
    for i := 0 to k do 
        for j := 0 to k do
            for b := 0 to k do 
                if (i+j+b) = s then
                    cnt := cnt + 1;
    if z = 1 then 
        writeln(cnt+3)
    else
    writeln(cnt);
end.