program nark;
var
  a:array[1..100000]of integer;
  n,i,m,j,ans:longint;
begin
  assign(input,'mark.in');
  assign(output,'mark.out');
  reset(input); rewrite(output);
  readln(n,m);
  for i:=1 to n do readln(a[i]);
  readln(ans);
  j:=1;
  for i:=1 to n do if a[i]>a[ans] then j:=j+1;
  i:=1;
  while (((i-1)*(n div m)+1>j)or(i*(n div m)<j)) and(i<=m) do I:=I+1;
  writeln(i);
  close(input); close(output);
end.