import java.util.Scanner;

class Main {

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

		int n = 0, x = 0;

		while(true){
			int sum = 0;
			n = scan.nextInt();
			x = scan.nextInt();
			if(n == 0 && x == 0)break;
			
			for(int i = 1; i <= n - 2; i++){
				for(int j = i + 1; j <= n - 1; 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