import java.util.*;
import java.text.*;

class Main {
    public static void main(String[]args)throws Exception {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            int x = sc.nextInt();
            int c = 0;
            if(n == 0 && x == 0) break;
            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) c++;
                    }
                }
            }
            System.out.println(c);
        }
    }
}
/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