import java.io.*;

class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        while(true) {
            String[] tmp = br.readLine().split(" ");
            int n = Integer.parseInt(tmp[0]);
            int x = Integer.parseInt(tmp[1]);
            if (n == 0 && x == 0) {
                break;
            }
            int count = 0;
            for(int i = 3;i <= n;i++){
                for(int j = 2;j < i;j++){
                    for(int k = 1;k < j;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