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 Go (1.6) (judge verdict: Time Limit Exceeded)

package main

import (
        "fmt"
)

func main() {
        var k, s int
        fmt.Scanf("%d %d", &k, &s)

        var cnt int

        for i := 0; i <= k; i++ {
                for j := 0; j <= k && i+j <= s; j++ {
                        for l := 0; l <= k; l++ {
                                if i+j+l == s {
                                        cnt++
                                }
                        }
                }
        }
        fmt.Println(cnt)

}