Which of the radio stations has the organization of ente público radio televisión madrid (eprtvm)?
CREATE TABLE "table1_23143607_1" (
  "autonomous_community" text,
  "organization" text,
  "television_channels" text,
  "radio_stations" text,
  "foundation" real
);
SELECT "radio_stations" FROM "table1_23143607_1" WHERE "organization"='Ente Público Radio Televisión Madrid (EPRTVM)';