sub sumTo {
    my $target = shift;
    for( 0 .. $#_ ) {
        if( $_[ $_ ] == $target )
            return 1;
        }
        else {
            if( sumTo( $target - $_[$_], @_[0 .. $_-1, $_+1 .. $#_] ) ) {
                return 1;
            }
        }
    }
    return 0;
}