#! /usr/bin/perl -w
use strict;

my $start = <>;
chomp $start;
my $end = <>;
chomp $end;

while (defined $start)
{
    if (not defined $end)
    {
	print $start;
	undef $start;
    }
    elsif ($start + 1 != $end)
    {
	print "$start,";
	$start = $end;
	$end = <>;
	chomp $end if defined $end;
    }
    else
    {
	my $newend = $end;
	do
	{
	    $end = $newend;
	    $newend = <>;
	    chomp $newend if defined $newend;
	} while defined $newend and $newend == $end + 1;
	print "$start-$end";
	print "," if defined $newend;
	$start = $newend;
	if (defined $start)
	{
	    $end = <>;
	    chomp $end if defined $end;
	}
    }
}

print "\n";