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 Ans = 0;
    if (S <= K)
      Ans = (S+1) * (S+2) / 2;
    else if (K < S && S <= 2*K)
      Ans = (K+1)*(K+1) - (2*K - S +1)*(2*K - S)/2 - (S -K +1)*(S-K)/2;
    else if (2*K <= S)
      Ans = (3*K -S +1)*(3*K - S +2)/2;
    System.out.println(Ans);
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz