import java.util.*;

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

        while(true){
            int n = sc.nextInt();
            int x = sc.nextInt();
            int a = 0;

            if(n == 0 && x == 0){
                break;
            }else{
                for(int i=1;i<n-1;i++){
                    for(int j=i+1;j<n;j++){
                        for(int k=j+1;k<n+1;k++){
                            if(i+j+k == x) a++;
                        }
                    }
                }
                System.out.println(a);
            }
        }
        sc.close();
    }
}

/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