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

namespace yuki_442
{
    class Program
    {
        static void Main(string[] args)
        {
            var t = scan;
            var x = t[0];
            var y = t[1];

            while (y > x || x % y != 0)
            {
                if (y > x)
                {
                    long k = y;
                    y = x;
                    x = k;
                }
                if (x % y != 0) x = x % y;
            }
            Console.WriteLine(y);
        }

        static long[] scan { get { return Array.ConvertAll(Console.ReadLine().Split(), long.Parse); } }
    }
}