How to Hide the "Lz Scrollbar Options" Admin Menu

function plt_hide_lz_scroll_bar_menus() {
	//Hide the "Settings → Lz Scrollbar Options" menu.
	remove_submenu_page('options-general.php', 'lzscrollbar-settings');
}

add_action('admin_menu', 'plt_hide_lz_scroll_bar_menus', 11);

Where do I put this code?