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

namespace Кварталы
{
    class Program
    {
        static public int QuarterCalculation(int x, int y)
        {
            if (x == y) //||(x % y == 0 || y % x == 0))
                return x;//Math.Max(x, y);
            var d = Math.Min(x, y);
            while (x % d != 0 || y % d != 0)
                d--;
            if (d == 1)
                return x + y - 1;
            else
            {
                x = x / d;
                y = y / d;
                return (x + y - 1) * d;
            }

        }

        static void Main(string[] args)
        {
            var str = "";
            var str1 = "";
            var str2 = "";
            int x, y;
            int i = 0;
            str = Console.ReadLine();
            while (str[i] != ' ')
            {
                str1 += str[i];
                i++;
            }
            i++;
            while (i < str.Length)
            {
                str2 += str[i];
                i++;
            }
            x = int.Parse(str1) - 1;
            y = int.Parse(str2) - 1;
            //Console.WriteLine(x);
            //Console.WriteLine(y);
            Console.WriteLine(QuarterCalculation(x, y));
        }
    }
}