using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("ENTER FIRST STRING: ");

     string S_ENT1 = Console.ReadLine();

        Console.WriteLine("ENTER SECOND STRING: ");

            string S_ENT2 = Console.ReadLine();

            bool a = false;

            //char[] digits = S_ENT1.ToCharArray();

            //bool isDigit = digits.Where(c => Char.IsDigit(c)).Count() != digits.Length ? false : true;

            //char[] digits2 = S_ENT2.ToCharArray();

            //isDigit = !isDigit ? false : digits2.Where(c => Char.IsDigit(c)).Count() != digits2.Length ? false : true;

            foreach (char c in S_ENT1)

            {

                if (!char.IsDigit(c))

                    a = true;

                else

                    a = false;

            }

            foreach (char b in S_ENT2)

            {

                if (!char.IsDigit(b))

                    a = true;

                else

                    a = false;

​

            }

            if (a==false)

            {

                long i = long.Parse(S_ENT1);

                long j = long.Parse(S_ENT2);

                long S_ENT3 = i + j;

                Console.WriteLine("this is addition of two numbers is: " + S_ENT3);

            }

            else

                Console.WriteLine("Give Both variables should be numbers only");

    }

}