@t=(0,1,1,2,3,2,1,0,1,2);
$"='.';
my %h=(
'1'=>	'a', 
'2'=>	'b', 
'3'=>	'c', 
'4'=>	'd', 
'5'=>	'e', 
'6'=>	'f', 
'7'=>	'g', 
'8'=>	'h', 
'9'=>	'i', 
'10'=>	'j',
'11'=>	'k',
'12'=>	'l',
'13'=>	'm',
'14'=>	'n',
'15'=>	'o',
'16'=>	'p',
'17'=>	'q',
'18'=>	'r');

my @s;
foreach my $t (@t)
{	
my $s;
my @id=map{$s++;($s%2 == 0)?$h{$_}:$_}map{$#s=$_;++$s[$_];@s}$t;
push(@out, "@id");
}

print @out;