#!/usr/bin/perl

use strict;
use warnings;
use DateTime::Format::Strptime;

my $fmt = DateTime::Format::Strptime->new(pattern => '%Y/%m/%d %H:%M:%S:%3N');

my $date1 = $fmt->parse_datetime('2006/01/03 03:59:59:671');
my $date2 = $fmt->parse_datetime('2006/01/03 04:00:00:562');

my $diff = $date2 - $date1;

print $diff->in_units('nanoseconds'), "\n";