using System;

​

namespace HelloWorld {

    public class Program

    {

        public static void Main()

        {

            Test Calc = new Test();

            Console.WriteLine(Calc.Differ(90, 23));

            Console.WriteLine(Calc.Concatter("so", "ny."));

            //test2

            int answer = 42;

            string greeting = "Hello, World!";

            double bigNumber = 1e100;

            System.Console.WriteLine("{0} {1} {2}", answer, greeting, bigNumber);

            //test3

            int year = 1066;

            string battle = "Battle of Hastings";

            Console.WriteLine("The {0} took place in {1}.", battle, year);

            int number = 12;

            int count = number + 40;

            Console.WriteLine(count);

        }

    }

    class Test 

    {

        public int Differ(int first, int second) 

        {

            return first-second;

        } 

        public string Concatter(string word1, string word2)

        {

            return word1+word2;

        }

    }

}