C#: Check whether the first two characters and last two characters of a given string are same

using System; // Importing the System namespace

namespace exercises // Defining a namespace called 'exercises'
{
    class Program // Defining a class named 'Program'
    {
        static void Main(string[] args) // The entry point of the program
        {
            // Output the results of the test function with different strings as arguments
            Console.WriteLine(test("abab")); // Pass "abab" to the test function and display the result
            Console.WriteLine(test("abcdef")); // Pass "abcdef" to the test function and display the result
            Console.WriteLine(test("xyzsderxy")); // Pass "xyzsderxy" to the test function and display the result
            Console.ReadLine(); // Wait for user input before closing the console window
        }

        // Function definition of the test function that takes a string 's1' as input and returns a boolean
        public static bool test(string s1)
        {
            // Compare the substring of the first 2 characters with the substring of the last 2 characters of 's1'
            return s1.Substring(0, 2) == s1.Substring(s1.Length - 2);
        }
    }
}