Problem with mktime not producing any output

I have a script I put together based on another script that I have seen posted here on this site.  Basically I want to take a hyphenated date and pass it to my script on STDIN and produce a perl/unix timestamp on STDOUT.  But for some reason, the the $timestamp variable isn't showing any output.  Can someone help?

#!/usr/bin/perl

use POSIX;

$hyphendate = shift;

($StoredMonth,$StoredDay,$StoredYear)=split(/-/,$hyphendate);

$sec = 0;
$min = 0;
$hour = 0;
$mday = $StoredDay;
$mon = $StoredMonth - 1;
$year = $StoredYear - 1900;
$wday = 0;
$timestamp = mktime($sec,$min,$hour,$mday,$mon,$year);
print "-> $timestamp <- $hyphendate\n"; Start Free Trial