#!/usr/bin/perl
# -*- mode: perl; coding: utf-8; tab-width: 4; -*-

use strict;
use warnings;

while (<DATA>) {
	chop;
	if (my ($q, $a) = split(/:/)) {
		print "$q:$a is\n";
		print "... ", decode(split(//, $q)), "\n";
	}
}

sub decode {
	return () unless my $a = shift;
	$a = ord($a) - ord('a') + 10 unless $a =~ /\d/;
	my $b = join('', splice(@_, 0, $a));
	my $c = $b % 26;
	my $d = chr(ord('a') + $c);
	print "\t$a($b) = ($b % 26 = $c) = $d\n";
	($d, &decode);
}

__DATA__
10:a
226:a
3520:a
19:j
210:k
3519:z
500001:b
2463579:uh
d4751402223934:c
a9028752798a6109452883a2566849612:abc
a5649689195b21787340956c103674010633d8575762736877e14014334193172:hello
361041222e13475130223949376248672:mario
a3489090677d38828797951984392273749796d37270023893329474049128631431043908e14421656917497d128536247791743915827955471828303314f200148040241576d1977125257653e24153309646860c102278187593f332708646701905