using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace clase2
{
    class Program
    {
        static void Main(string[] args)
        {
            //vars to use
            int a, b, c ,res;
            Boolean ban ;

            //Default values
            a = 0;
            b = 0;
            c = 0;
            ban = true;

            //Input
            Console.WriteLine("digite dato 1");
            a = int.Parse(Console.ReadLine());

            Console.WriteLine("digite dato 2");
            b = int.Parse(Console.ReadLine());

            //Operation
            do
            {
                Console.WriteLine("digite 1:SUM , 2:RESTA");
                res = int.Parse(Console.ReadLine());
                if(res == 1){
                    c = a + b;
                    ban = false;
                }else if(res == 2){
                    c = a - b;
                    ban = false;
                }
            } while (ban);

            //Output
            Console.Write("Resultado es : " + c);
            Console.ReadLine();
        }
    }
}