InPut :
$str = "abcdefghiaabccdjklm";

OutPut :

$str="efghijklm";


##</code><code>##


Original String :
my $str = "abcdeffghijkllmnoppqestqaserb";

1st iteration :
$str =~ s/(\w)(.*)\1/$2/g;
Output : bcdeffghijkllmnoppqestqserb 

2nd Iteration :
$str =~ s/(\w)(.*)\1/$2/g;
OutPut : cdeffghijkllmnoppqestqser

3rd Iteration :
$str =~ s/(\w)(.*)\1/$2/g;
OutPut : cdffghijkllmnoppqestqsr 

4th Iteration :  Gets rid of consecutive elements
$str =~ s/(\w)(.*)\1/$2/g;
OutPut: cdghijkmnoestsr