import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        
        while(true){
            int sum = 0;
            int n = sc.nextInt();
            int x = sc.nextInt();
            
            if(n == 0){
                break;
            }
            
            for(int i = 1; i <= n; i++){
                for(int j = i + 1; j <= n; j++){
                    for(int k = j + 1; k <= n; k++){
                        if(i + j + k == x){
                            sum++;
                        }
                    }
                }
            }
            
            System.out.println(sum);
        }
    }
}


/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