How to Hide the "Specifc Weather Counter" Admin Menu

function plt_hide_tct_specific_weather_day_menus() {
	//Hide the "Settings → Specifc Weather Counter" menu.
	remove_submenu_page('options-general.php', 'tct_spd');
}

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

Where do I put this code?