var n,i,k,j,m,s,r:longint;
    a:array[1..16000] of longint;
    
begin
  assign(input,'transport.in');
  assign(output,'transport.out');
  reset(input);
  rewrite(output);
  read(n,k);
  m:=0; s:=0;
  for i:=1 to n do begin
    read(a[i]);
    if a[i]>m then m:=a[i];
    s:=s+a[i];
  end;
  s:=(s-1) div k + 1;
//  write(s,' ',m);
  if s>m then m:=s;
  j:=0;
  s:=0;
  r:=m;
  for i:=1 to n do begin
    if j+a[i]<=m then j:=j+a[i]
    else begin
      inc(s);
      if s=k then j:=j+a[i]
      else j:=a[i];
    end;
    if j>r then r:=j;
  end;
  write(r);
end.