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: Wrong Answer)

program taskH;
var k,s,sum,x,y,z,temp:longint;
begin
readln(k,s);
for x:=0 to k do
begin
  y:=s-x;
  temp:=k*2;
  if y>temp then
  continue;
  if y=temp then
    begin
    sum:=sum+1;
    end;
  if y<temp then
  begin
    for y:=0 to k-x do
    begin
      if y+k<s then
      break
      else
      sum:=sum+1;
    end;
  end;
end;
writeln(sum);
end.