using System;
using System.Collections.Generic;
using System.Linq;

namespace yukicoder
{
	public class Program
	{
		public static long X;
		public static void Main()
		{
			var a = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();
			Euclid(a[0] , a[1]);
			Console.WriteLine(X);
		}
		static void Euclid(long a, long b)
		{
			var c = Math.Max(a, b);
			var d = Math.Min(a, b);
			var e = c % d;
			if (e > 0)
			{
				Euclid(e, d);
			}
			else
			{
				X = d;
			}
		}
	}
}