using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = long.Parse(line[0]);
        var b = long.Parse(line[1]);
        var res = gcd(a, b);
        if (a % 2 == 0 && b % 2 == 0) res *= 2;
        Console.WriteLine(res);
    }
    public static long gcd(long a, long b)
    {
        if (a < b) return gcd(b, a);
        while (b != 0)
        {
            var w = a % b;
            a = b;
            b = w;
        }
        return a;
    }
}