sub two_sum_Discipulus {
    my ($input, $target) = @_;
    foreach my $index ( 0 .. $#$input ){
		( $_ != $index and $input->[$_] + $input->[$index] == $target ) ? 
                return [$index, $_]                                     :   0 
                for 0 .. $#$input;
	}
}