use strict;

my %hash;
while (<DATA>) {
   chomp;
   my @chars = split '';
   for my $char (@chars) {
      # use the next line if case doesn't matter
      # $hash{lc $char}++;
      $hash{$char}++;
   }
   print join " ", @chars, "\n";
}

my $consensus = '';
for (sort keys %hash) {
   $consensus = $_ if $hash{$_} > $hash{$consensus};
   print "\$hash{$_}: $hash{$_}\n";
}
print "\nChar: '$consensus' has the highest count: $hash{$consensus}!\n";

__DATA__
aAabbbbcdDeeeeEEefFFffffffffffff
zzzzzzzxxxxxxxxxyyYyg