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 2.6.2) (judge verdict: Time Limit Exceeded)

var k,s,a,b,c,d,e,f,sum : longint ;
begin
 readln(k,s);
 for a:=0 to k do
  for b:=a to k do
   for c:=b to k do
    begin
     if a+b+c=s then
      begin
      if (a<>b)and(a<>c)and(c<>b) then
       sum:=sum+6
      else if (a=b)and(a<>c)  then
       sum:=sum+3
      else if (b=c)and(b<>a) then
       sum:=sum+3
      else if (a=c) and (a<>c) then
       sum:=sum+3
      else
       sum:=sum+1;
 //      writeln(a,b:2,c:2,sum:2);
     end;
    end;
 writeln(sum);
end.