import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

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

		while (true) {
			final int n = sc.nextInt();
			final int x = sc.nextInt();
			
			if(n == 0 && x == 0){
				break;
			}
			
			int count = 0;
			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){
							count++;
						}
					}
				}
			}
			
			System.out.println(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