import java.util.*;

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

		while(true){
			final String[] data = sc.nextLine().split(" ");
			final int n = Integer.parseInt(data[0]);
			final int x = Integer.parseInt(data[1]);
			if(n == 0 && x == 0) break;
			int count = 0;
			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) 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