How to Hide the "Back To Top Button" Admin Menu

function plt_hide_back_to_top_button_menus() {
	//Hide the "Back To Top Button" menu.
	remove_menu_page('seos-back-to-top-settings');
}

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

Where do I put this code?