using System;

public class Program

{

    public static void Main()

    {

           int a = 5; 

​

            int b = 4; 

​

            Console.WriteLine(a + b); //9 

​

            Console.WriteLine(a + b++); //9 

​

            Console.WriteLine(a + b); //10 

​

            Console.WriteLine(a + (++b) ); //11 

​

            Console.WriteLine(a + b); //11 ;

    }

}