program ex;
type
 ss=array[0..1000]of integer;
var
 f:ss;
 n,m,x,p:integer;
procedure init;
 var
  i,j:integer;
  flag:boolean;
 begin
  assign(input,'mark.in');
  assign(output,'mark.out');
  reset(input);
  rewrite(output);
  readln(n,m);
  p:=n div m;
  for i:= 1 to n do read(f[i]);
  readln(x);
  x:=f[x];
  close(input);
 end;
procedure main;
 var
  i,j,k,y,t,w:integer;
 begin
  for i:=1 to n-1 do
   for j:=i+1 to n do
    if f[i]<f[j] then
     begin
      f[i]:=f[i]+f[j];
      f[j]:=f[i]-f[j];
      f[i]:=f[i]-f[j];
     end;
  k:=1;
  t:=1;w:=1;
  y:=f[1];
  for i:=1 to n do
   begin
    if f[i]=y then inc(w)
              else begin
                    y:=f[i];
                    t:=t+w;
                   end;
    if t>=(k+1)*p then inc(k);
    if f[i]=x then begin
                    writeln(k);
                    close(output);
                    exit;
                   end;
   end;
 end;
begin
 init;
 main;
end.