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

class Magatro
{
    static void Main()
    {
        string[] ab = Console.ReadLine().Split(' ');
        Array.Sort(ab);
        long A = long.Parse(ab[0]);
        long B = long.Parse(ab[1]);
        Console.WriteLine(G(A,B ));
    }
    static long G(long a,long b)
    {
        long r = a % b;
        while (r != 0)
        {
            a = b;
            b = r;
            r = a % b;
        }
        return b;
    }
}