using System;

public class Program

{

    public static void Main()

    {

        string number = "124235245423523423", number2 = "3423525232332325423";//here length varies between strings

        for(int i=number.Length-1;i>=0;i--){

        int sum = int.Parse(number[i].ToString()) + int.Parse(number2[i].ToString());

        Console.WriteLine(sum);

        }   

    }

}