#!/usr/bin/perl
$user=<STDIN>;
$pass=<STDIN>;
open(F,"passwd");
open(Fout,">passwd.new");
while(<F>)
{
	@record = split(/:/,$_);
	$newvalue = @record[2];
	if( ($user =~ /@record[0]/) && ($pass =~ /@record[1]/) && ($newvalue != 0))
{
		$newvalue-=1;
	}
	print Fout "@record[0]:@record[1]:$newvalue";
}
close(Fout);
close(F);
rename('passwd.new','passwd');
