"use strict";
function Main(input) {
  const args = input.split(' ').map(m => parseInt(m));
  let N = args.shift();
  let L = args.shift();
  let pie = [];
  for (let i = 0; i < N; i++) {
    pie.push(L + i);
  }
  console.log(pie);
  pie.sort((a, b) => {
    let a1 = a > 0 ? a : -a;
    let b1 = b > 0 ? b : -b;
    return a1 - b1;
  });
  console.log(pie);
  pie.shift();
  console.log(pie.reduce((p ,c) => p + c));
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
