program project5;

var
  n, t, i, j, min: longint;
  w, sum, f: array[0..34567] of longint;
begin
  readln(n, t);
  for i := 1 to n do
    Read(w[i]);
  for i := 1 to n do
  begin
    sum[i] := sum[i - 1] + w[i];
    f[i] := -maxlongint;
  end;
  min := -maxlongint;
  for i := 1 to n do
    for j := 0 to i - 1 do
    begin
      if f[j] + (sum[i] - sum[j]) * i - t > f[i] then
        f[i] := f[j] + (sum[i] - sum[j]) * i - t;
      if f[i] > min then
        min := f[i];
    end;
  writeln(min);
end.