import java.util.Scanner;
class Main{
	public static void main(String[]agrs){
		Scanner sc = new Scanner(System.in);
		while(sc.hasNext()){
			int n = sc.nextInt();
			int x = sc.nextInt();
			if(n == 0 && x == 0) break;
			int count = 0;
			for(int i = 1; i <= n; i++){
				for(int j = 1; j <= n; j++){
					for(int k = 1; k <= n; k++){
						if(i + j + k == x && i != j
								&& j != k && i != k){
							count++;
						}
					}
				}
			}
			System.out.println(count/6);
		}
	}
}
/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