using System;

namespace First

{

    public class Program

    {

        public static void Main()

        {

            Math a=new Math();

            int num1,num2;

            Console.WriteLine("1:Addition");

            Console.WriteLine("2:Subtraction");

            Console.WriteLine("3:Multiplication");

            Console.WriteLine("4:Division");

            int choice=Convert.ToInt32(Console.ReadLine());

            Console.WriteLine(choice);

            switch(choice)

            {

                case 1: Console.WriteLine("Enter two numbers:");

                        num1=Convert.ToInt32(Console.ReadLine());

                        num2=Convert.ToInt32(Console.ReadLine());

                        Console.WriteLine("Total:"+a.add(num1,num2));

                        break;

                case 2: Console.WriteLine("Enter two numbers:");

                        num1=Convert.ToInt32(Console.ReadLine());

                        num2=Convert.ToInt32(Console.ReadLine());

                        Console.WriteLine("Total:"+a.sub(num1,num2));

                        break;

                case 3: Console.WriteLine("Enter two numbers:");

                        num1=Convert.ToInt32(Console.ReadLine());

                        num2=Convert.ToInt32(Console.ReadLine());

                        Console.WriteLine("Total:"+a.mult(num1,num2));

                        break;

                case 4: Console.WriteLine("Enter two numbers:");

                        num1=Convert.ToInt32(Console.ReadLine());

                        num2=Convert.ToInt32(Console.ReadLine());

                        Console.WriteLine("Total:"+a.div(num1,num2));

                        break;

            }

        }

    }

    public class Math

    {

        public int add(int a,int b)

        {

            return a+b;

        }

        public int sub(int a,int b)

        {

            return a-b;

        }

        public int mult(int a,int b)

        {

            return a*b;

        }

        public int div(int a,int b)

        {

            return a/b;

        }

    }

}