program day1b
    implicit none

    character(300) :: data_line
    character(1) :: test_char
    integer :: num1, num2
    integer :: numsum
    integer :: running_total = 0
    integer :: i, istat
    integer :: i2, strlen
    integer, parameter :: max_iterations = 10000

    integer :: n_arguments
    character(200) :: fname
    n_arguments = command_argument_count()
    if (n_arguments .eq. 1) then
        call get_command_argument(1, fname)
        print *, "File: ", fname
    else
        print *, "Wrong number of arguments: ", n_arguments
        stop
    end if
    open(10, file=fname)
    do i=1,10000
        read(10, "(A)", iostat = istat) data_line
        if (is_iostat_end(istat)) then
            exit
        end if
        num1 = -1
        num2 = -1
        strlen = len_trim(data_line)
        do i2=1,strlen
            test_char = data_line(i2:i2)
            if ((test_char .ge. '0') .and. (test_char .le. '9')) then
                read(test_char, *) num2
                if (num1 .eq. -1) then
                    num1 = num2
                end if
            end if
        end do
        if (num1 .ne. -1) then
            numsum = num1 * 10 + num2
            running_total = running_total + numsum
            write(*, 20) num1, num2, numsum, data_line(1:strlen)
        end if
    end do
    close(10)

    print *
    print *, "Sum of calibration values: ", running_total
20  format(i1, i2, i4, '| ', a)
end program day1b