import java.util.Scanner;

class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int n, x;
        while(true){
            n = scan.nextInt();
            x = scan.nextInt();
            if(n == 0 && x == 0) break;
            System.out.println(calcCombi(n, x));
        }
    }
    public static int calcCombi(int n, int x){
        if(x < 6) return 0;
        int i, j, k;
        int count = 0;
        for(i = 1; i <= n; i++){
            for(j = i + 1; j <= n; j++){
                for(k = j + 1; k <= n; k++){
                    if(i + j + k == x) count++;
                }
            }
        }
        return 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