#!/usr/bin/perl

use strict;
use warnings;

my @Eq = (
    " ABC + DDE =  FCF",
    "  CB + BGE =  BCA",
    " AEE + CBG = DGAE",
    " ABC +  CB =  AEE",
    " DDE + BGE =  CBG",
    " FCF + BCA = DGAE",
);

my @res = &Sol(@Eq);

foreach my $r (@res)
{
   print join("; ", map { "$_ = $r->{$_}" } keys %{$r}), "\n";
}

sub Sol
{
   my (@e) = @_;

   my %pairs = ();
   my @sol = ();

   for (@e)
   {
      s!=!==!;
      $pairs{$_} = 0 foreach (m!(\w)!g);
   }

   my @vars = keys %pairs;
   my $count = scalar @vars;

   while($pairs{$vars[$count-1]} < 10)
   {
      my $true = 0;
      foreach my $e (@e)
      {
         while(my($k, $v) = each %pairs)
         {
            $e =~ s!$k!$v!g;
         }

         $true = eval $e;
         last unless $true;
      }

      push @sol, {%pairs} if $true;

      my $i = 0;
      while($i < $count)
      {
         last if ++$pairs{$vars[$i]} < 10;
         $pairs{$vars[$i]} = 0;
         $i++;
      }
   }

    return @sol;
}