open(IN,"+<datum");

while(<IN>) 
{
	if (/sister/)
	{
		
                $where=tell(IN);
                $add="and brothers";
                seek(IN,$where,0);
                print IN "$add";
		next;
	
	}
	
	else
	{
		@lines = split(/\n+/);
				next;
	}
	
}


close IN;