import std.stdio, std.string, std.conv, std.range, std.algorithm;

void main() {
    int[] tmp = readln.split.to!(int[]);
    int n = tmp[0], l = tmp[1];
    auto apple = iota(l, l+n).array.sort!("a * a < b * b");
    writeln(apple.sum - apple[0]);    
}