import java.util.Arrays;
import java.util.Scanner;
public class Main {
    
    
    
     public static void main(String[] args) {
        
         Scanner sc = new Scanner(System.in);
         int A = sc.nextInt();
         int L = sc.nextInt();
          int b[ ] = new int[A];
         int a[ ] = new int[A];
         for(int i = 0 ; i<A ; i++){
                   a[i]  =  i+1;
             
         }
         
       for(int i = 0 ; i<A ; i++){
               b[i]=  L+a[i]-1;
           
       }  
         Arrays.sort(b);
         int sum = 0 ;
         for(int i=0; i<b.length ; i++){
             sum+=b[i];
             
         }
         int bestsofar=Integer.MAX_VALUE;
         int ans=0;
         for(int i=0;i<A;i++)
         {
         int cur=sum-b[i];
         int diff=Math.abs(b[i]);
         if(diff<bestsofar)
         {
             ans=cur;
             bestsofar=diff;
         }
         }
      //   System.out.println(b[1]+b[2]+b[3]+b[4]+b[5]);
         System.out.println(ans);
         
    }
}

/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