num 1 to ... with 3 steps

using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.Design;
using System.Globalization;
using System.Net.Http.Headers;
using System.Reflection;
using System.Runtime.ConstrainedExecution;
using System.Security.Cryptography;

namespace SomeExcercises
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            for (int i = 1; i <= n; i += 3)
            {
                Console.WriteLine(i);
            }


        }
    }
}