#!/usr/bin/perl

use strict;
use warnings;

while(<>){
     chomp;
     while(/(.*)(\([^\(]+([^\(]+?)+\))(.*)/g){
		my $vorn = $1;
		my $klammer = $2;
		my $hinter = $4;
		$klammer =~ s/ /@/g;
		$text = $vorn.$klammer.$hinter;
	}
}