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 (Clang 3.8.0) (judge verdict: Time Limit Exceeded)

#include <stdio.h>

int ans;
int num;
int ret = 0;

int main() {
  scanf("%d %d", &ans, &num);
  int i, j, k;
  for (i = 0; i <= ans; i++) {
    if (i == num) {
      ret++;
      break;
    }
    for (j = 0; j <= ans; j++) {
      if (i + j == num) {
        ret++;
        break;
      }
      for (k = 0; k <= ans; k++) {
        if (i + j + k == num) {
          ret++;
          break;
        }
      }
    }
  }

  printf("%d\n", ret);
}