import java.util.Scanner;


public class Main {

	public static void main(String [] args) {
		
		Scanner sc = new Scanner(System.in);
		
		while(true) {
			
			long ways = 0;
			
			
			long n = sc.nextInt();
			long x = sc.nextInt();
			
			if(n == 0 && x == 0) break;
			
			for(long i = 1;i <= n -2;i++) {  //一個目の数（n-2通り）
				
				for(long j = i + 1;j <= n - 1;j++) {  //二個目の数（それぞれn-i-1）通り
					
					for(long k = j + 1;k <= n;k++) {
						if(i + j + k == x)ways++;
						
					}
					
				}
				
			}
			
			System.out.println(ways);
			
			
		}

	}
	

}

/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