Fibbonacci Sequence

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FibonacciNumbers
{
    class FibonacciNumbers
    {
        static void Main(string[] args)
        {
//Write a program that reads a number N and prints on the console the first N members of the Fibonacci sequence (at a single line, separated by comma and space - ", ") : 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, ….
//On the only line you should print the first N numbers of the sequence, separated by ", " (comma and space)
//1 <= N <= 50   N will always be a valid positive integer number

            int n = int.Parse(Console.ReadLine());
            int firstNum = 0;
            int secondNum = 1;
            int thirdNum = 0;
            if (n>=1&&n<=50)
            {

                if (n == 1)
                {
                    Console.WriteLine(firstNum);
                }
                else if (n == 2)
                {
                    Console.WriteLine("{0}, {1}", firstNum, secondNum);
                }
                else if (n > 2)
                {
                    Console.Write("{0}, {1}, ", firstNum, secondNum);
                    for (int i = 1; i <= n - 2; i++)
                    {
                        thirdNum = firstNum + secondNum;
                        firstNum = secondNum;
                        secondNum = thirdNum;
                        if (n - 2 == i)
                        {
                            Console.WriteLine(thirdNum);
                        }
                        else
                        {
                            Console.Write(thirdNum + ", ");
                        }
                    }
                }
            }
        }
    }
}