Error in procedure

CREATE OR ALTER PROCEDURE VLR_CLASSE(P_REF_ANOMES NUMERIC(04),P_CDG_ORGAO NUMERIC(03),  
      P_CLASSE VARCHAR(02))
RETURNS(R_VALOR NUMERIC(13,2)) 

AS
  
BEGIN
   R_VALOR = 0;


   SELECT 
       C.VLR_CLASSE
     FROM 
       TBCLASSE C
     WHERE (C.CDG_ORGAO = :P_CDG_ORGAO)
       AND (RTRIM(C.CLASSE) = RTRIM(:P_CLASSE))
       AND (C.DTA_INI_CLASSE = (SELECT MAX(C2.DTA_INI_CLASSE) 
                               FROM TBCLASSE C2 
                               WHERE (CAST(CAST(EXTRACT(YEAR FROM C2.DTA_INI_CLASSE) || LPAD(EXTRACT(MONTH FROM C2.DTA_INI_CLASSE),2,'0') AS VARCHAR(10))AS NUMERIC(10)) <= :P_REF_ANOMES)
                                 AND C2.CDG_ORGAO = C.CDG_ORGAO 
                                 AND C2.CLASSE = C.CLASSE))
    INTO :R_VALOR; 

  IF (R_VALOR IS NOT NULL) THEN 
     BEGIN
      R_VALOR = COALESCE(R_VALOR,0);       
     END

  
   SUSPEND;
END;