using System;

public class Program

{

    public static void Main()

    {

        var input = "aggga";

        var isPalindrome = IsPalindrome(input);

        Console.WriteLine($"Is palindrome: {isPalindrome}");

    }

    private static bool IsPalindrome(string input)

    {

        int i = 0, j = input.Length - 1;

        while(i <= j)

        {

            if (input[i] != input[j]) return false;

            i++;

            j--;                

        }

        return true;

    }

}