my $n = shift or die; while( $n % 2 == 0 ){ print "2\n"; $n /= 2; } for( $_ = 3; $_ <= (my $sqrt || sqrt($n)); $_+= 2 ){ while( $n % $_ == 0 ){ print "$_\n"; $n /= $_; } } print "$n\n" if $n > 1