Write the entire User class so that it securely manages user credentials for a login system.

• The user's password must be stored in a private field that cannot be accessed or modified directly from outside the class.
• The username must be accessible and settable publicly using a property.
• Provide a protected method that checks if a given password matches the stored password.
• Implement a constructor that initializes both the username and the password.
• Add a public method TryLogin that accepts an input password, checks it using the protected validation method, and prints either Login successful or Login failed to the console.
• Use the correct access modifiers for all members to ensure security and correct visibility.
• Do not include any code outside of the User class except for the provided Program class and Main method.