program main
    implicit none
    character(100) :: S
    integer :: i, code, length

    read *, S

    length = len_trim(S)

    do i = 1, length
        code = iachar(S(i:i))

        if (code >= iachar('A') .and. code <= iachar('Z')) then
            S(i:i) = achar(code + 32)
        else
            S(i:i) = achar(code - 32)
        end if
    end do

    print *, trim(S)
end program main