import java.util.Scanner;

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

        int i ,j ,k ,count;

        while(true){
            int n = sc.nextInt();
            int x = sc.nextInt();
            count = 0;

            if(n == 0 && x == 0)break;

            for(i = 1;i <= n;i++){
                for(j = i + 1;j <= n;j++){
                    for(k = j + 1;k <= n;k++){
                        if(i + j + k == x){
                            count++;
                        }
                    }
                }
            }

            System.out.printf("%d\n",count);

        }
    }
}

/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