AoC 2019 Day4 FORTRAN

PROGRAM DAY4
  INTEGER :: A,B,C,D,E,F,PASSWORD(6)
  INTEGER :: LOWER, UPPER,PART1,PART2,POWERS(6)
  LOGICAL :: OK(2)
  CHARACTER(LEN=13) :: INLINE

  OPEN(1,FILE="input.txt")
  READ(1,*)INLINE
  CLOSE(1)
  READ(INLINE(1:6),*)LOWER
  READ(INLINE(8:),*)UPPER
  PART1=0
  PART2=0
  POWERS=(/(10**I,I=5,0,-1)/)

  OUTER:DO A=LOWER/10**5,UPPER/10**5
     DO B=A,9
        DO C=B,9
           DO D=C,9
              DO E=D,9
                 DO F=E,9
                    PASSWORD=(/A,B,C,D,E,F/)
                    IF(SUM(PASSWORD*POWERS)<LOWER)CYCLE
                    IF(SUM(PASSWORD*POWERS)>UPPER)EXIT OUTER
                    OK=CHECK(PASSWORD)
                    IF(OK(1))PART1=PART1+1
                    IF(OK(2))PART2=PART2+1
                 END DO
              END DO
           END DO
        END DO
     END DO
  END DO OUTER

  WRITE(*,'("Part 1: ",I0)') PART1
  WRITE(*,'("Part 2: ",I0)') PART2

CONTAINS
  FUNCTION CHECK(PASSDIGITS) RESULT(RES)
    INTEGER :: PASSDIGITS(6),I
    LOGICAL :: RES(2)
    RES=.FALSE.
    DO I=1,5
       IF(PASSDIGITS(I).EQ.PASSDIGITS(I+1))THEN
          RES(1)=.TRUE.
          IF(I.EQ.1.OR.PASSDIGITS(I-1).NE.PASSDIGITS(I))THEN
             IF(I.EQ.5.OR.PASSDIGITS(I+2).NE.PASSDIGITS(I))THEN
                RES(2)=.TRUE.
                EXIT
             END IF
          END IF
       END IF
    END DO
  END FUNCTION CHECK
END PROGRAM DAY4