#!usr/local/bin/perl

$filename = "input.txt";
open (FILE,"<$filename");
@fileinput=<FILE>;
close(FILE);

foreach $line(@fileinput)
{
 my $test=($line);

#add written by and capital the first letter of each word
  if($test=~s/AU: \b(\w+)|AU: \b(w+)\s\b(w+)/AU: Written by: \u$1 \u$2/g)
   {
     print $test;
   }
}