How to Hide Init Review System Admin Menus

function plt_hide_init_review_system_menus() {
	//Hide the "Review System" menu.
	remove_menu_page('init-review-system');
	//Hide the "Review System → Settings" menu.
	remove_submenu_page('init-review-system', 'init-review-system');
	//Hide the "Review System → Manage Reviews" menu.
	remove_submenu_page('init-review-system', 'init-review-management');
}

add_action('admin_menu', 'plt_hide_init_review_system_menus', 12);

Where do I put this code?