import java.io.*;
import java.util.*;


public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        int l = in.nextInt();
        int [] a = new int[n];
        for (int i = 0; i < a.length; i++) {
            a[i] = l + i;
        }
        
        int min = Integer.MAX_VALUE;
        for (int i = 0; i < a.length; i++) {
            if(Math.abs(a[i]) < Math.abs(min)) {
                min = a[i];
            }
        }
        int sum = 0;
        for (int i = 0; i < a.length; i++) {
            if(a[i]!=min) {
                sum+=a[i];
            }
        }
        out.println(sum);
        out.flush();
    }

    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
}
class Point {
    private int value;
    private int index;
    public int getValue() {
        return value;
    }
    public int getIndex() {
        return index;
    }
    public Point(int value,int index) {
        this.value = value;
        this.index = index;
    }

}

class InputReader extends BufferedReader {
    StringTokenizer tokenizer;

    public InputReader(InputStream inputStream) {
        super(new InputStreamReader(inputStream), 32768);
    }

    public InputReader(String filename) {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    }

    public Integer nextInt() {
        return Integer.valueOf(next());
    }
    public Long nextLong() {return  Long.valueOf(next());}

    static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        }

        public OutputWriter(Writer writer) {
            super(writer);
        }

        public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        }

        public void close() {
            super.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