How to Hide Ultimate floating widgets Admin Menus

function plt_hide_ultimate_floating_widgets_menus() {
	//Hide the "Ultimate floating widgets" menu.
	remove_menu_page('ultimate_floating_widgets');
	//Hide the "Ultimate floating widgets → Ultimate floating widgets" menu.
	remove_submenu_page('ultimate_floating_widgets', 'ultimate_floating_widgets');
	//Hide the "Ultimate floating widgets → Upgrade to PRO" menu.
	remove_submenu_page('ultimate_floating_widgets', 'https://www.aakashweb.com/wordpress-plugins/ultimate-floating-widgets/?utm_source=admin&utm_medium=menu&utm_campaign=ufw-pro#pro');
}

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

Where do I put this code?