sub decode2 {
	my $total = shift;
	my $delta;
	my $diff;
	foreach (@_) {
		$delta += $_;
		$diff += $delta;
	}
	my $original= ($total-$diff)/(@_+1);
	my $value= $original;
	my @results= map { $value += $_ } @_;
	return ($original, @results);
}