#!/usr/bin/perl -w
use strict;

while (<DATA>) {
    chomp;
    my $max = 0;
    my $count = 1;
    my $direction = 0;
    my $last = substr $_, 0, 1;
    for my $this (split //) {
        local $_ = $this - $last;
        ++$count and next if $direction and $_ % 10 == $direction;
        $count = 2 if $direction = abs==1 || abs==9 ? $_ % 10 : 0;
    } continue {
        $max = $max > $count ? $max : $count;
        $last = $this;
    }
    print "$_\t=> $max\n";
}

__DATA__
82665409266027476709324472
2468
2345678
78901
78909
32109
32101
909
09090