I am trying to round only three corners of the following rectangle below. I know this is easy to do in Illustrator CC, but I don't have it. 

In Illustrator CS6 you can only round the corners of a shape using **Effect > Stylize > Round Corners**. However, this results in all of the corners being rounded. 

Is there any way to make only three corners of the rectangle rounded using Illustrator CS6? Any help is appreciated.

[![enter image description here](https://i.stack.imgur.com/XOWtT.png)](https://i.stack.imgur.com/XOWtT.png)