Convert RFC3501 date to Unix epochx

When I'm trying to sort mails I got, there is only date in RFC3501, such as 'Thu, 15 Mar 2012 15:46:10 +0800'. I don't want to impor too many modules, so I write this. Just a prototype. And need to handle the timezone and time with only single digit.

#!/usr/bin/perl -w
#

sub ConvertRFC3501toUnixTime{
    my $input = shift;


    #Thu, 15 Mar 2012 15:46:10 +0800
    my %months = ("Jan" => 1,"Feb" => 2,"Mar" => 3,"Apr" => 4,"May" => 5,"Jun" => 6,"Jul" => 7,"Aug" => 8,"Sep" => 9,"Oct" => 10,"Nov" => 11,"Dec" => 12);
    my($day,$mon,$year,$hour,$min,$sec) = $input =~ /(\d{2}) (\w{3}) (\d{4}) (\d{2}):(\d{2}):(\d{2})/;

    my $time = $sec.$min.$hour.$day.($months{$mon}-1).($year - 1900);
    return $time;
}





my $str = 'Thu, 28 Mar 2012 15:46:10 +0800';
print localtime;
print "\n";
print ConvertRFC3501toUnixTime($str);