import java.math.BigInteger;
import java.util.Arrays;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String[] inputData = input.nextLine().split(" ");
        int row = Integer.parseInt(inputData[0]);
        int col = Integer.parseInt(inputData[1]);

        BigInteger matrix[][] = new BigInteger[row][col];

        BigInteger startNumber = new BigInteger("1");

        for (int r = 0; r < row; r++) {
            matrix[r][0] = startNumber;
            for (int c = 1; c < col; c++) {
                matrix[r][c] = ((matrix[r][c - 1]).multiply(new BigInteger("2")));
            }
            startNumber = startNumber.multiply(new BigInteger(("2")));
        }


        int currentRow = 1;
        int currentCol = 1;
        BigInteger sum = new BigInteger("1");

        int hMovement = 1;
        int vMovemet = 1;

        while (row!=1 &&col!=1) {
                    boolean checkerRows= false;
                    boolean checkerCols= false;

            if (currentCol == 0 || currentCol == col - 1) {
                hMovement = hMovement * (-1);
                checkerCols=true;
            }
            if (currentRow == 0 || currentRow == row - 1) {
                vMovemet = vMovemet * (-1);
                checkerRows=true;
            }
            if (checkerCols == true && checkerRows == true){
                break;
            }
            BigInteger res = matrix[currentRow][currentCol];
            sum=sum.add(res) ;
            currentRow=currentRow+vMovemet;
            currentCol=currentCol+hMovement;
        }
        if (row!=1 &&col!=1){
            BigInteger res = matrix[currentRow][currentCol];
            sum=sum.add(res) ;
        }

            System.out.println(sum);
    }

}