type deque=^nod;
     nod=record
        next:deque;
        niv,val:longint;
        end;

var
s:qword;
n,i,j,x,k:longint;
c,p,q:deque;


begin
assign(input,'deque.in');
assign(output,'deque.out');
reset(input);
rewrite(output);
read(n,k);   s:=0;
read(x);new(p); p^.val:=x; p^.next:=nil;P^.niv:=1; q:=p;
for i:=2 to n do
        begin


        read(x);
        if q^.niv<=i-k then q:=q^.next;
        p:=q;

        while (p^.val<x) and (p^.next<>nil) do p:=p^.next;
        if p^.val<x then
                        begin
                        new(c);
                        c^.val:=x;
                        C^.niv:=i;
                        c^.next:=nil;
                        p^.next:=c;
                        end

        else
                        begin
                        p^.val:=x;
                        p^.niv:=i;
                        P^.next:=nil;
                        end;
        if i>=k then inc(s,q^.val);
        end;



write(s);
close(input);
close(output);
end.