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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<limits.h>

int main(){
	int k,s;
	scanf("%d %d",&k,&s);
	
	int x,y,z;
	int pattern=0;
	
	for(x=k;x>0;x--){
		for(y=s-x;y>=0;y--){
			if(y>k){
				continue;
			}
			
			if(y>x){
				continue;
			}
			
			z = s-x-y;
			if(z>y){
				break;
			}
			
			if(x==y && y==z){
				pattern+=1;
			}else if(x!=y && y!=z && x!=z){
				pattern+=6;
			}else{
				pattern+=3;
			}
			
		}
	}
	
	printf("%d",pattern);
	
	return 0;
}