How to Hide MapifyLite Admin Menus

function plt_hide_mapifylite_menus() {
	//Hide "MapifyLite".
	remove_menu_page('mapify.php');
	//Hide "MapifyLite → Map Settings".
	remove_submenu_page('mapify.php', 'edit.php?post_type=map');
	//Hide "MapifyLite → Map Locations".
	remove_submenu_page('mapify.php', 'edit.php?post_type=map-location');
	//Hide "MapifyLite → MapifyPro Installer".
	remove_submenu_page('mapify.php', 'mapifypro-installer');
}

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

Where do I put this code?