---

using System;

class Program
{
    static void Main()
    {
        int A = int.Parse(Console.ReadLine());
        int B = int.Parse(Console.ReadLine());

        while (A != B)
        {
            if (A > B)
            {
                A = A - B;
            }
            else
            {
                B = B - A;
            }
        }

        Console.WriteLine(A);
    }
}