uses math;
const maxn = 10000;
      fi = '';
      fo = '';
var n:word;
    k:byte;
    a: array[1..maxn] of integer;
    f: array[0..maxn] of longint;
    res:longint;
procedure enter;
var i,j:word;
begin
  assign(input,fi);
  reset(input);
  assign(output,fo);
  rewrite(output);
  readln(n,k);
  f[0]:=0;
  res:=0;
  for i:=1 to n do
  begin
    read(a[i]);
    f[i]:=trunc(-10e9);
    if i=1 then f[i]:=max(0,a[i])
    else
      for j:=i-1 downto max(0,i-k) do
      f[i]:=max(f[i],f[j]+a[i]);
    if f[i]>res then res:=f[i];
  end;
  writeln(res);
  close(input);
  close(output);
end;
begin
  enter;
end.

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