#!/usr/bin/perl
# vi:ts=4 sw=4 et:
use strict;
use warnings;

my $str = <<'EOS';
$r->vor;
$r->vor;
$r->vor;
$r->drehe_rechts;
$r->vor;
$r->vor;
$r->drehe_links;
$r->vor;
$r->vor;
$r->vor;
$r->vor;
$r->vor;
drehe_um;
$r->vor;
EOS

my @elements = split( /\n/, $str );
my ( $last, $cnt ) = ( '', 0);

for my $i ( 0 .. $#elements ) {

    if ( $elements[$i] ne $last and $i != 0 ) {

        print $last, ( $cnt > 1 ? "($cnt)" : ''), $/;

        $cnt=1;
        $last = $elements[$i];
        next;
    }

    $last = $elements[$i];
    $cnt++;
}

print $last, $/;