while (<DATA>) {
	chomp;
	my $line = $_;
	my @chars = split '';
	my $diff = join '', map {($chars[$_+1] - $chars[$_]) % 10} (0..$#chars-1);

	my $maxlen = 0;
	my $maxpos = 0;
	while ($diff =~ m/(1+|9+)/g) {
		if ($maxlen < length $1) {
			$maxlen = length $1;
			$maxpos = pos($diff) - $maxlen;
		}
	}
	printf "pos = % 2s, str = '%s'\n", $maxpos, substr($line, $maxpos, $maxlen + 1);
}