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

# same as "sum -s file"   use System V sum algorithm, use 512 bytes blocks

my $buf; 
open (FH,"< $0");
read( FH, $buf, -s FH );
close FH;

my $checksum = unpack("%32C*",$buf) %32767;  

print "$checksum\n";

exit;