#!/usr/bin/perl
use strict;
use warnings;

my $bin =  0b1111_1111_1111;

for my $factor (3,5) {
	# round up to multiple of 4
	my $shift = $factor + (-$factor % 4); 
	my $c = $bin >> $shift;
	$c <<= $shift;
	printf "%b\n", $c;
}