How to Hide MapPress Maps for WordPress Admin Menus

function plt_hide_mappress_google_maps_for_wordpress_menus() {
	//Hide the "MapPress" menu.
	remove_menu_page('mappress');
	//Hide the "MapPress → Settings" menu.
	remove_submenu_page('mappress', 'mappress');
	//Hide the "MapPress → Map Library" menu.
	remove_submenu_page('mappress', 'mappress_maps');
}

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

Where do I put this code?