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 x,y,z,s,k,n,i,ct:longint;
begin
  ct:=0;
  readln(k,s);
  y:=s-k;
  z:=k-y;
  for x:=0 to k do begin
  while z>=0 do begin
         ct:=ct+1;
         y:=y+1;
         z:=z-1;
   end;
   if k=s then
     y:=0
   else if k-x-1<=s then
     y:=0 
   else y:=s-k-x-1;
   z:=s-x-y-1;
   end;
   if s=(k*3) then
    writeln(1)
   else writeln(ct);
end.