type sir= array [1..1000] of longint;
var n,k,c,s,i:longint;
x:sir;
function maxim(var n: longint):longint;
var max, i: longint;
begin
max:=-maxint;
for i:=1 to n do
        if x[i]> max then max:=x[i];
maxim:=max;
end;
function minim(var n: longint):longint;
var min, i: longint;
begin
min:=maxint;
for i:=1 to n do
        if x[i]< min then min:=x[i];
minim:=min;
end;
begin
read(n);readln(k);
for i:= 1 to n do
        readln(x[i]);
if n=k then c:=maxim(n)

 else if n>k then begin
         s:=0;
         for i:= 1 to n do
                s:=s+x[i];
         c:=s-maxim(n);
         if c< maxim(n) then c:=maxim(n)
          else if k=1 then c:=s
          else if c mod (k-1)<>0 then c:=maxim(n)+minim(n);
         end;
 writeln(c);
 end.