Unique Visitor Tracker

In this problem, you will create a program that adds multiple visitor IDs to a HashSet to automatically exclude duplicates and displays the unique visitor count to standard output.

Learning Objective: Understand how to exclude duplicates using Set from collection Framework

Overview

Create a program to record website visitor IDs and count unique visitors by removing duplicates. Visitor IDs are given as integers, and the same ID may be recorded multiple times. Use Set to automatically exclude duplicates and display the final unique visitor count.

Input Format

The first line contains the number of visitor IDs n.
The next n lines each contain a visitor ID (integer).

Output Format

Output the unique visitor count in the format "Unique visitors: X".

Constraints

• 1 ≤ n ≤ 1000
• Visitor IDs are integers from 1 to 10000

Key Points

• Using HashSet automatically excludes duplicates
• The size() method gets the count of unique elements
• The add() method adds elements