How to Hide Solid Security Basic Admin Menus

function plt_hide_better_wp_security_menus() {
	//Hide the "Security" menu.
	remove_menu_page('itsec');
	//Hide the "Security → Setup" menu.
	remove_submenu_page('itsec', 'itsec');
	//Hide the "Security → Get More Security" menu.
	remove_submenu_page('itsec', 'itsec-go-pro');
}

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

Where do I put this code?