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Hello All,
I am stuck in below trailhead chanllange
Create a Visualforce page that displays the first name of the logged-in user.

The page must be named 'DisplayUserInfo'.
The displayed user information must be generated dynamically from the logged-in user.

Here below is my code. Please help me to find the solution.
<apex:page>
{!$User.FirstName } {!$User.LastName } ({!$User.Username })
</apex:page>