import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int n, l;
        n = sc.nextInt();
        l = sc.nextInt();
       
        int[] aji = new int[n];
        int minIndex = 0;
        for(int i=0; i<n;i++)
        {
            aji[i] = l+i;
            if(i > 0){
                if(Math.abs(aji[i]) < Math.abs(aji[minIndex]))
                {
                    minIndex = i;
                }
            }
        }

        int sum = 0;
        for(int i=0; i<n;i++){
            if(i != minIndex)
            {
                sum += aji[i];
            }
        }
        System.out.println(sum);
        
        
    }
}


/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