$n=<>;
$l=ab;
while($n){
	$r=2+sqrt($n)|0;
	while($r*($r+1)>$n){
		--$r;
	}
	print$l x$r;
	$n-=$r*($r+1);
	if($n>=$r+1){
		print substr $l,0,1;
		$n-=$r+1;
	}
	$l=~y/a-z/c-zab/;
}