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: Wrong Answer)

var max,sum,ans,x,y,z:longint;


begin
   readln(max,sum);
   ans:=0;
   for x := 0 to max do begin
      for y := 0 to x do begin
	     for z := 0 to y do begin
		    if x+y+z=sum then 
			 begin
			    inc(ans);
				 if x<>y then inc(ans);
				 if z<>y then inc(ans);
				 if x<>z then inc(ans);
		     end;
		  end;
	   end;
	end;
	writeln(ans);
end.