#!/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(1)
  {
     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++;
     }
     last if $i == $count;
  }

   return @sol;
}