How to override default style in rad controls?

[Bb]

Suppose I am using two RadTextBox control and I want to differentiate those two using css.

    <telerik:RadTextBox ID="rtb_1" runat="server"></telerik:RadTextBox>
    <telerik:RadTextBox ID="rtb_1" runat="server"></telerik:RadTextBox>

For example when I hover over , this gets generated..please find attached image..

Now, If I apply style here..

    .riHover {
                background: red !important; 
            }

This will get apply on every input controls of this page, but I want to apply it over first textbox control.

How can I achieve that??