Remove unwanted stuff in Contact Form 7 from function.php

For the people using contact form 7 for wordpress, it's knew that this plugin adds automatically some stuff in the output code. The normal output looks like this:

<span class="wpcf7-form-control-wrap">
<input type="text" name="" value="" size="40" class="wpcf7-form-control wpcf7-text wpcf7-validates-as-required" aria-required="true" aria-invalid="false">        
</span>

plus some tags, paragraphs ecc... Is there a way to remove all the

<span>, <br>, <p> 

from the output leaving only the input fields? I need this to be done from function.php so i can safetly update the plugin in the future.

via Chebli Mohamed