How to Hide Smart Icons For Wordpress Admin Menus

function plt_hide_smartifw_menus() {
	//Hide the "SmartIcons" menu.
	remove_menu_page('smart-icons-for-wordpress');
	//Hide the "SmartIcons → SmartIcons" menu.
	remove_submenu_page('smart-icons-for-wordpress', 'smart-icons-for-wordpress');
	//Hide the "SmartIcons → Add-ons" menu.
	remove_submenu_page('smart-icons-for-wordpress', 'smart-ifw-pro-addons-page');
}

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

Where do I put this code?