How to Hide Footer Contacts Bar Admin Menus

function plt_hide_dn_footer_contacts_menus() {
	//Hide "Footer Contacts Bar".
	remove_menu_page('dn_footer_contacts_manage');
	//Hide "Footer Contacts Bar → Footer Contacts Bar".
	remove_submenu_page('dn_footer_contacts_manage', 'dn_footer_contacts_manage');
	//Hide "Footer Contacts Bar → Settings".
	remove_submenu_page('dn_footer_contacts_manage', 'dn_footer_contacts_manage&view=settings');
	//Hide "Footer Contacts Bar → Statistics".
	remove_submenu_page('dn_footer_contacts_manage', 'dn_footer_contacts_manage&view=stats');
	//Hide "Footer Contacts Bar → About".
	remove_submenu_page('dn_footer_contacts_manage', 'dn_footer_contacts_manage&view=about');
}

add_action('admin_menu', 'plt_hide_dn_footer_contacts_menus', 21);

Where do I put this code?