SUBROUTINE YMDSEC (YMD,  SECPST)
C
C     ********************************************
C
C     INPUT:  YMD(1) = YEAR
C             YMD(2) = MONTH
C             YMD(3) = DAY
C             YMD(4) = HOUR
C             YMD(5) = MINUTE
C             YMD(6) = SECOND
C
C     OUTPUT: SECPST = SECONDS PAST 1950
C
C     ********************************************
C
      INTEGER YMD(6),SECPST,UTC(5)
C
C     ********************************************
C
      IF (YMD(2).GE.1 .AND. YMD(2).LE.12) THEN
      CALL YMDUTC (YMD,  UTC)
      CALL UTCSEC (UTC,  SECPST)
      ELSE
      SECPST = 0
      ENDIF
      RETURN
      ENDPROGRAM