How to Hide Advert Manage Admin Menus

function plt_hide_ad_manage_menus() {
	//Hide "Adverts".
	remove_menu_page('ad-manager');
	//Hide "Adverts → Adverts".
	remove_submenu_page('ad-manager', 'ad-manager');
	//Hide "Adverts → New Advert".
	remove_submenu_page('ad-manager', 'am-advert');
	//Hide "Adverts → Locations".
	remove_submenu_page('ad-manager', 'am-locations');
	//Hide "Adverts → Settings".
	remove_submenu_page('ad-manager', 'am-settings');
}

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

Where do I put this code?