In the spirit of TIMTOWTDOI...

#!/usr/bin/perl
use strict;
use warnings;

my @input=<DATA>;

for my $input (@input) {
  chomp $input;
  my @characters=split//,$input;
  my $output;
  for my $i (0..$#characters) {
    $output .= "-" if ($i == 4 || $i == 6);
    $output .= $characters[$i];
  }
  print $output,$/;
}

__END__
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