def remove_nested_parens(s):
    """
        Returns a copy of "s" with parenthesized text removed.
        Nested paretheses are handled properly.
    """
    
    result = ""
    paren_level = 0
    
    for c in s:
        if c == "(":
            paren_level += 1
        elif (c == ")") and paren_level:
            paren_level -= 1
        elif not paren_level:
            result += c

    return result