var a:array[1..20]of longint;
n,k,i,s,p:longint;
f,g:text;
begin
assign(f,'transport.in');reset(f);
assign(g,'transport.out');rewrite(g);
read(f,n,k);
for i:=1 to n do begin
read(f,a[i]);readln(f);end;
repeat
for i:=2 to n do
if s<a[1] then s:=s+a[i] else begin p:=p+1;s:=0;s:=a[i];end;
if p>k then begin a[1]:=a[1]+1;p:=0;end;until p=k;
write(g,a[1]);close(f);close(g);end.