sub check_field {
    my $file_name = shift;

    open my $fh, "<$file_name"
        or die "*** ERROR opening '$file_name': $!";

    my @fields = ();

    while (defined (<$fh>)) {
       if ($. == 2) {
           chomp;
           @fields = split /;/;
           return 0 unless $#fields == 3;
           last;
       }
    }

    return 0 if $#fields < 0;
    return $fields[2] =~ /^\d+$/;
}