from abc import ABC, abstractmethod

class HtmlBuilder:
    def __init__(self):
        self.html = ""

    def add_element(self, element):
        self.html += element.render()

    def get_html(self):
        return self.html

class HtmlElement(ABC):
    @abstractmethod
    def render(self):
        pass

class Div(HtmlElement):
    def render(self):
        return "<div></div>\n"

class Label(HtmlElement):
    def render(self):
        return "<label>Label</label>\n"

class Input(HtmlElement):
    def render(self):
        return "<input type='text'/>\n"

class Select(HtmlElement):
    def render(self):
        return "<select><option>Option</option></select>\n"

class Submit(HtmlElement):
    def render(self):
        return "<input type='submit'/>\n"