# Process the next lines of data until line containing string "TF      Unknown" is reached.
foreach (<MOTIFS>)
  {
        # Remove the end of line character.
        chomp my $line;
        # Process lines until "TF Unknowm'
        while ($line ne 'TF      Unknown')
          {
          # Declare a variable to hold the data in the file.
          my %base_pairs;

          # Split the string into 5 parts, using whitespace as a separator.
          # Assuming the Position is always in the same order in the file.
          (undef, $base_pairs{A}, $base_pairs{C}, $base_pairs{G}, $base_pairs{T}) = split /\s+/, $line, 5;
          my @letters = keys %base_pairs;

          # Start with the first column value and make it the max. value.
          my $max = pop @letters;

          # Compare each value to the maximum.
          foreach my $letter (@letters)
             {
             # What if two (or more) values are equal???
             if ($base_pairs{$max} < $base_pairs{$letter})
                 {
                 # The current value was greater than the maximum, so make it the new maximum.
                 $max = $letter;
                 }
             }

  # Print the letter representing the maximum value.
          print $max;
         }
      }
   }
# print an end of line character.
print "\n";