using System;

public class Program

{

    public static void Main()

    {

        int a,c,result;

        Console.WriteLine("a-c+4");

        Console.WriteLine("A=");

        a = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("C=");

        c = Convert.ToInt32(Console.ReadLine());

        result = a-c+4;

        Console.WriteLine("a-c+4=" + result);

    }

}

​