using System;

public class Program

{

    public static float Add(int num1,int num2){

        return num1+num2;

    }

    public static float Sub(int num1,int num2){

        return num1-num2;

    }

    public static float Mul(int num1,int num2){

        return num1*num2;

    }

    public static float Div(int num1,int num2){

        return num1/num2;

    }

    public static void Main()

    {

    string val1,val2,val3;

      int num1,num2;

        int again=0;

        do{

            Console.WriteLine("Enter First number");

        val1 = Console.ReadLine();

        num1 = Convert.ToInt32(val1);

        Console.WriteLine("Enter Second number");

        val2 = Console.ReadLine();

        num2 = Convert.ToInt32(val2);

        Console.WriteLine("Enter 1 for addititon , 2 for sub , 3 for mul , 4 for div");

        string op;

        int opVal;

         op = Console.ReadLine();

        opVal = Convert.ToInt32(op);

        if(opVal==1)

           Console.WriteLine(Add(num1,num2));

        else if(opVal==2)

           Console.WriteLine(Sub(num1,num2));

        else if(opVal==3)

           Console.WriteLine(Mul(num1,num2));

        else if(opVal==4)

           Console.WriteLine(Div(num1,num2));

        else Console.WriteLine("Invalid Option");

            Console.WriteLine("Press 1 to continue");

            val3 = Console.ReadLine();

        again = Convert.ToInt32(val3);

        }

        while(again==1);

    }

}