#!/usr/local/bin/perl -l
#
use strict;
use warnings;

$_ = q{DFR7234C__A_B_C_Bonzo_Dog_D_B};
print;

1 while s
   {
      (?<=__)
      [A-Z]_
   }
   {}x;

print;
print q{-} x 25;

$_ = q{DFR7234C__A_B_C_Bonzo_Dog_D_B};
print;

s
   {
      (?<=__)
      [A-Z]_
      (?{
            print pos();
            pos() = 0;
            print pos()
        })
   }
   {}gx;

print;
print q{-} x 25;