Click on button based on its Value in Selenium Python

There is HTML code like bellow:

<input type="button" name="" value="back" onclick="window.history.back(1)" class="back-btn">

and I want to click on it based on its value (back):

elements = driver.find_elements_by_link_text('back')
for element in elements:
    element.click()

But it does not work.