program aa;
var
ar:array[1..1000] of integer;
br:array[1..1000] of integer;
i,j:integer;
n,k,l,x,o,u,p:integer;
f,f1:text;
begin
l:=0;
 assign(f,'chess.in');assign(f1,'chess.out');
 reset(f);rewrite(f1);
 readln(f,n,k);
 for i:=1 to n do
  readln(f,ar[i]);
  for i:=1 to n do
   for j:=1 to n do
    if (ar[i]>ar[j]) then begin
    inc(l);
    br[l]:=ar[i]-ar[j];
    end;
    for i:=1 to l-1 do
     for j:=i to l do
      if  br[i]>br[j] then begin
      x:=br[i];
      br[i]:=br[j];
      br[j]:=x;
      end;
      o:=k div 2;
      u:=k mod 2;
      for i:=1 to o do
       p:=p+br[i];
      write(f1,p*2+br[k]*u);


 close(f);close(f1);
end.