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

namespace Bounce
{
    internal class Program
    {
        static void Main(string[] args)
        {
            int[] input = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int rows = input[0];
            int cols = input[1];
            ulong[,] board = new ulong[rows, cols];

            for (int row = 0; row < rows; row++)
            {
                for (int col = 0; col < cols; col++)
                {

                    board[row, col] = (ulong)Math.Pow(2, row + col);

                }
            }
            int startRow = 1;
            int startCol = 1;
            int directionRow = 1;
            int directionCol = 1;
            ulong sum = 1;

            if (rows == 1 || cols ==1)
            {
                Console.WriteLine(sum);
                return;
            }


            while (!HitCorner(rows, cols ,startRow, startCol))
            {
                sum += board[startRow, startCol];

                if (directionRow == 1)
                {
                    startRow++;
                }
                else
                {
                    startRow --;
                }

                if (directionCol == 1)
                {
                    startCol++;
                }
                else
                {
                    startCol--;
                }

                if(startRow >= rows)
                {
                    directionRow = 0;
                    startRow -= 2;
                }
                else if(startRow < 0)
                {
                    directionRow = 1;
                    startRow+=2;
                }

                if (startCol >= cols)
                {
                    directionCol = 0;
                    startCol -= 2;
                }
                else if(startCol < 0)
                {
                    directionCol = 1;
                    startCol+=2;
                }
                if (rows == 1)
                {
                    startRow = 0;
                }
            }
            sum += board[startRow, startCol];
            Console.WriteLine(sum);
        }



        private static bool HitCorner(int rows, int cols, int startRow, int startCol)
        {
            return startRow == rows - 1 && startCol == 0
                || startCol == cols - 1 && startRow == 0 ||
                startCol == cols - 1 && startRow == rows - 1 ||
                startRow == 0 && startCol == 0;
        }
    }
}