class Program
    {
        static void Main(string[] args)
        {
            string numA = Console.ReadLine();
            string numB = Console.ReadLine();
            if(numA.Length < numB.Length)
            {
                string str = numA;
                numA = numB;
                numB = str;
            }

            string ans = "";
            ans = numA.Substring(0, numA.Length - numB.Length);
           
            for(int i = 0; i < numB.Length; i++)
            {
                if (numA[numA.Length - numB.Length + i] != numB[i])
                {
                    ans += "1";
                }
                else
                {
                    ans += "0";
                }
            }
            Console.WriteLine(Convert.ToInt32(ans,2));
        }
    }