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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);

		int K = s.nextInt();
		int S = s.nextInt();

		int answer = 0;
		for (int x = 0; x <= K; x++) {
			if (x > S)
				break;
			for (int y = 0; y <= K; y++) {
				if (x + y > S)
					break;

				int z = S - x - y;
				if(z<=K) {
					answer ++;
				}
				/*
				for (int z = 0; z <= K; z++) {
					if (x + y + z > S)
						break;

					if(x+y+z == S) {
						answer++;
					}

				}
				*/
			}
		}

		System.out.println(answer);

	}

}