 The ones who get a white ball serve in a Batallón del Servicio Militar Nacional (National Military Service Battalion) composed entirely of one-year SMN conscripts.In certain cities, such as Veracruz and Ciudad Madero, the lottery system also includes a blue ball; whoever draws it must serve in the navy.In 2003, President Vicente Fox Quesada reformed the law to allow for voluntary military service to be performed by females of military age.