How to Hide Polylang Admin Menus

function plt_hide_polylang_menus() {
	//Hide "Languages".
	remove_menu_page('mlang');
	//Hide "Languages → Languages".
	remove_submenu_page('mlang', 'mlang');
	//Hide "Languages → Settings".
	remove_submenu_page('mlang', 'mlang_settings');
	//Hide "Languages → Setup".
	remove_submenu_page('mlang', 'mlang_wizard');
	//Hide "Languages → Lingotek".
	remove_submenu_page('mlang', 'mlang_lingotek');
}

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

Where do I put this code?