How to change this permalink?

One of my site using wordpress has this permalink structure

I don't like it at all because it has unnecessary info, I want it like this

How can I change this permalink structure?

Thanks for your help.

 

Go to Settings/Permalinks and use %postname% in the custom field. And this plugin http://wordpress.org/extend/plugins/wp-no-category-base/

 

There's no need of any plugin's. You can do it by the method he mentioned here.