How to convert Less file to a Sass file with less2sass
Ruby gem: https://rubygems.org/gems/less2sass/versions/1.0.1
Step 1: Install gem less2sass
Command: gem install less2sass
Step 2: Convert datepicker3.less to datepicker3.sass
Command: less2sass datepicker3.less datepicker3.sass
Finish, Good luck!
Another methods: http://csspre.com/convert/